Method for receiving reference signal in wireless communication system and apparatus therefor

ABSTRACT

Disclosed is a method for receiving a channel state information (CSI)-reference signal (RS) by a user equipment (UE) in a wireless communication system, which includes: receiving a CSI-RS associated with the SSB, in which the CSI-RS may be assumed to be quasi co-located (QCL) with the SSB.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/064,290, filed on Jan. 8, 2019, which is a National Stage filingunder 35 U.S.C. 371 of International Application No. PCT/KR2018/000169,filed on Jan. 4, 2018, which claims the benefit of U.S. ProvisionalApplication No. 62/442,995, filed on Jan. 6, 2017, U.S. ProvisionalApplication No. 62/444,316, filed on Jan. 9, 2017, U.S. ProvisionalApplication No. 62/501,114, filed on May 4, 2017, U.S. ProvisionalApplication No. 62/555,698, filed on Sep. 8, 2017, and U.S. ProvisionalApplication No. 62/566,516, filed on Oct. 1, 2017.

The contents of which are all hereby incorporated by reference herein intheir entirety.

TECHNICAL FIELD

The present invention relates to wireless communications, and moreparticularly, to a method for receiving a reference signal of a userequipment based on QCL assumption and an apparatus for the same.

BACKGROUND ART

Mobile communication systems have been developed to provide voiceservices, while guaranteeing user activity. Service coverage of mobilecommunication systems, however, has extended even to data services, aswell as voice services, and currently, an explosive increase in traffichas resulted in shortage of resource and user demand for a high speedservices, requiring advanced mobile communication systems.

The requirements of the next-generation mobile communication system mayinclude supporting huge data traffic, a remarkable increase in thetransfer rate of each user, the accommodation of a significantlyincreased number of connection devices, very low end-to-end latency, andhigh energy efficiency. To this end, various techniques, such as smallcell enhancement, dual connectivity, massive Multiple Input MultipleOutput (MIMO), in-band full duplex, non-orthogonal multiple access(NOMA), supporting super-wide band, and device networking, have beenresearched.

SUMMARY

An object of the present invention is to improve a reception performanceof a reference signal of a terminal through Quasi-co-Location (QCL)assumption in a wireless communication system.

Furthermore, an object of the present invention is to define a QCLassumption operation for beam management in a wireless communicationsystem.

The technical objects to attain in the present invention are not limitedto the above-described technical objects and other technical objectswhich are not described herein will become apparent to those skilled inthe art from the following description.

A method for receiving a channel state information (CSI)-referencesignal (RS) by a user equipment (UE) in a wireless communication systemaccording to an embodiment of the present invention includes: receivinga CSI-RS associated with the SSB, in which the CSI-RS may be assumed tobe quasi co-located (QCL) with the SSB.

Furthermore, the SSB may include a primary synchronizationsignal/sequence (PSS), the SSS, and/or a physical broadcast channel(PBCH).

Furthermore, in the method for receiving the CSI-RS by the UE, themethod may further include receiving QCL information for indicating theQCL assumption between the CSI-RS and the SSB, in which the QCLinformation may indicate an index of the SSB and a QCL type for a QCLparameter set to which the QCL assumption is applied.

Furthermore, the QCL information may be received through radio resourcecontrol (RRC) signaling.

Furthermore, the QCL type may be defined to indicate different QCLparameter sets for each QCL type.

Furthermore, the QCL parameter set may include a delay spread, a Dopplerspread, a Doppler shift, an average gain, an average delay, and/or aspatial reception parameter.

Furthermore, the spatial reception parameter may include a receivingbeam direction parameter and/or a receiving beam width relatedparameter.

Furthermore, the QCL type indicated for the QCL assumption with the SSBmay be restricted to a specific QCL type in advance.

Furthermore, a QCL parameter set indicated by the specific QCL type mayinclude the average delay, the Doppler shift, and/or the spatialreception parameter.

Furthermore, when the CSI-RS is mapped to a plurality of CSI-RSresources, application of the QCL assumption may be selectivelyindicated in units of each CSI-RS resource.

Furthermore, the indication for the application is received through theRRC signaling.

Furthermore, when the QCL assumption corresponds to a partial QCLassumption, it may be assumed that the QCL parameter of the CSI-RScorresponds to a sub-set of a QCL parameter derived from the SSB.

Furthermore, the CSI-RS may correspond to a periodic CSI-RS or aperiodicCSI-RS.

Furthermore, the CSI-RS may be a CSI-RS transmitted for a purpose ofbeam management.

Furthermore, a user equipment (UE) for receiving a channel stateinformation (CSI)-reference signal (RS) in a wireless communicationsystem according to another embodiment of the present inventionincludes: a radio frequency (RF) unit transmitting and receiving a radiosignal; and a processor controlling the RF unit, in which the processormay receive a synchronization signal/sequence block (SSB) and a CSI-RSassociated with the SSB by controlling the RF unit, and the CSI-RS maybe assumed to be quasi co-located (QCL) with the SSB.

According to an embodiment of the present invention, a parameter inrelation to a reception beam is defined as a new QCL parameter; there isan effect that a reception performance is more improved in a spatialaspect of an RS of a user equipment.

In addition, according to an embodiment of the present invention, sinceGCL assumption for different types of RSs is available, which brings thesame effect as a density of a specific RS is increased, and accordingly,there is an effect that a reception performance of the corresponding RSis improved.

In addition, according to an embodiment of the present invention, sinceQCL signaling is indicated to a user equipment in a hierarchicalsignaling scheme, there is an effect that semi-static QCL indicationconsidering an instantaneous situation is available as well as signalingoverhead may be reduced.

Further, according to an embodiment of the present invention, since aCSI-RS is received based on the QCL assumption with an SSB, receptionperformance of the CSI-RS is enhanced. Moreover, when the QCL assumptionis received for receiving the CSI-RS for the beam management, a QCLassumption operation for the beam management may be supported and moreefficient beam management is available.

It will be appreciated by persons skilled in the art that that theeffects that can be achieved through the present invention are notlimited to what has been particularly described hereinabove and otheradvantages of the present invention will be more clearly understood fromthe following detailed description.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention.

FIGS. 1A and 1B show the structures of a radio frame in a wirelesscommunication system to which an embodiment of the present invention maybe applied.

FIG. 2 is a diagram illustrating a resource grid for one downlink slotin a wireless communication system to which an embodiment of the presentinvention may be applied.

FIG. 3 shows the structure of a downlink subframe in a wirelesscommunication system to which an embodiment of the present invention maybe applied.

FIG. 4 shows the structure of an uplink subframe in a wirelesscommunication system to which an embodiment of the present invention maybe applied.

FIG. 5 illustrates a self-contained subframe structure to which thepresent invention may be applied.

FIG. 6 exemplifies a sub-array partition model, which is a first TXRUvirtualization model option.

FIG. 7 exemplifies a full-connection model, which is a second TXRUvirtualization model option.

FIGS. 8A and 8B illustrate reference signal patterns mapped to downlinkresource block pairs in a wireless communication system to which thepresent invention may be applied.

FIGS. 9A through 9C are diagrams illustrating a service area for eachTXRU.

FIG. 10 illustrates an antenna panel model in which analog beamformingis applied for each panel to which the present invention may be applied.

FIG. 11 illustrates a scheme in which a single CSI-RS resource is mappedper panel according to an embodiment of the present invention.

FIG. 12 illustrates a scheme in which a plurality of CSI-RS resources ismapped per panel according to an embodiment of the present invention.

FIG. 13 illustrates a scheme in which CSI-RS resource shared by aplurality of panels is mapped according to an embodiment of the presentinvention.

FIG. 14 is a diagram illustrating duration of an SS block and an SSburst which may be applied to the present invention.

FIG. 15 is a diagram illustrating an SS burst configuration for a TDDcase which may be applied to the present invention.

FIGS. 16A and 16B illustrate a type 1 CSI-RS and a type 2 CSI-RS whichmay be applied to the present invention.

FIG. 17 is a diagram illustrating a QCL assumption scheme depending on atype 2 CSI-RS configuration according to an embodiment of the presentinvention.

FIG. 18 is a diagram illustrating a (required) QCL indication fora type2 CSI-RS resource according to an embodiment of the present invention.

FIG. 19 is a diagram illustrating an overall DL beam managementprocedure according to an embodiment of the present invention.

FIG. 20 is a flowchart illustrating a CSI-RS receiving method by a UEaccording to an embodiment of the present invention.

FIG. 21 illustrates a block diagram of a wireless communicationapparatus according to an embodiment of the present invention.

MODE FOR INVENTION

Some embodiments of the present invention are described in detail withreference to the accompanying drawings. A detailed description to bedisclosed along with the accompanying drawings are intended to describesome exemplary embodiments of the present invention and are not intendedto describe a sole embodiment of the present invention. The followingdetailed description includes more details in order to provide fullunderstanding of the present invention. However, those skilled in theart will understand that the present invention may be implementedwithout such more details.

In some cases, in order to avoid that the concept of the presentinvention becomes vague, known structures and devices are omitted or maybe shown in a block diagram form based on the core functions of eachstructure and device.

In this specification, a base station (BS) (or eNB) has the meaning of aterminal node of a network over which the base station directlycommunicates with a device. In this document, a specific operation thatis described to be performed by a base station may be performed by anupper node of the base station according to circumstances. That is, itis evident that in a network including a plurality of network nodesincluding a base station, various operations performed for communicationwith a device may be performed by the base station or other networknodes other than the base station. The base station (BS) may besubstituted with another term, such as a fixed station, a Node B, an eNB(evolved-NodeB), a Base Transceiver System (BTS), an access point (AP),g-NodeB (gNB), New RAT (NR) or 5G-NodeB. Furthermore, the device may befixed or may have mobility and may be substituted with another term,such as User Equipment (UE), a Mobile Station (MS), a User Terminal(UT), a Mobile Subscriber Station (MSS), a Subscriber Station (SS), anAdvanced Mobile Station (AMS), a Wireless Terminal (WT), a Machine-TypeCommunication (MTC) device, a Machine-to-Machine (M2M) device, or aDevice-to-Device (D2D) device.

Hereinafter, downlink (DL) means communication from an eNB to UE, anduplink (UL) means communication from UE to an eNB. In DL, a transmittermay be part of an eNB, and a receiver may be part of UE. In UL, atransmitter may be part of UE, and a receiver may be part of an eNB.

Specific terms used in the following description have been provided tohelp understanding of the present invention, and the use of suchspecific terms may be changed in various forms without departing fromthe technical sprit of the present invention.

The following technologies may be used in a variety of wirelesscommunication systems, such as Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA), Time Division Multiple Access(TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), SingleCarrier Frequency Division Multiple Access (SC-FDMA), and Non-OrthogonalMultiple Access (NOMA). CDMA may be implemented using a radiotechnology, such as Universal Terrestrial Radio Access (UTRA) orCDMA2000. TDMA may be implemented using a radio technology, such asGlobal System for Mobile communications (GSM)/General Packet RadioService (GPRS)/Enhanced Data rates for GSM Evolution (EDGE). OFDMA maybe implemented using a radio technology, such as Institute of Electricaland Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),IEEE 802.20, or Evolved UTRA (E-UTRA). UTRA is part of a UniversalMobile Telecommunications System (UMTS). 3rd Generation PartnershipProject (3GPP) Long Term Evolution (LTE) is part of an Evolved UMTS(E-UMTS) using evolved UMTS Terrestrial Radio Access (E-UTRA), and itadopts OFDMA in downlink and adopts SC-FDMA in uplink. LTE-Advanced(LTE-A) is the evolution of 3GPP LTE.

Embodiments of the present invention may be supported by the standarddocuments disclosed in at least one of IEEE 802, 3GPP, and 3GPP2, thatis, radio access systems. That is, steps or portions that belong to theembodiments of the present invention and that are not described in orderto clearly expose the technical spirit of the present invention may besupported by the documents. Furthermore, all terms disclosed in thisdocument may be described by the standard documents.

In order to more clarify a description, 3GPP LTE/LTE-A is chieflydescribed, but the technical characteristics of the present inventionare not limited thereto.

General System to which the Present Invention May be Applied

FIGS. 1A and 1B show the structure of a radio frame in a wirelesscommunication system to which an embodiment of the present invention maybe applied.

3GPP LTE/LTE-A support a radio frame structure type 1 which may beapplicable to Frequency Division Duplex (FDD) and a radio framestructure which may be applicable to Time Division Duplex (TDD).

FIG. 1A illustrates the radio frame structure type 1. A radio frameconsists of 10 subframes. One subframe consists of 2 slots in a timedomain. The time taken to send one subframe is called a TransmissionTime Interval (TTI). For example, one subframe may have a length of 1ms, and one slot may have a length of 0.5 ms.

One slot includes a plurality of Orthogonal Frequency DivisionMultiplexing (OFDM) symbols in the time domain and includes a pluralityof Resource Blocks (RBs) in a frequency domain. In 3GPP LTE, OFDMsymbols are used to represent one symbol period because OFDMA is used indownlink. An OFDM symbol may be called one SC-FDMA symbol or symbolperiod. An RB is a resource allocation unit and includes a plurality ofcontiguous subcarriers in one slot.

FIG. 1B illustrates the frame structure type 2. The radio framestructure type 2 consists of 2 half frames. Each of the half framesconsists of 5 subframes, a Downlink Pilot Time Slot (DwPTS), a GuardPeriod (GP), and an Uplink Pilot Time Slot (UpPTS). One subframeconsists of 2 slots. The DwPTS is used for initial cell search,synchronization, or channel estimation in UE. The UpPTS is used forchannel estimation in an eNB and to perform uplink transmissionsynchronization with UE. The guard period is an interval in whichinterference generated in uplink due to the multi-path delay of adownlink signal between uplink and downlink is removed.

In the frame structure type 2 of a TDD system, an uplink-downlinkconfiguration is a rule indicating whether uplink and downlink areallocated (or reserved) to all subframes. Table 1 shows theuplink-downlink configuration.

TABLE 1 Uplink- Downlink-to- Downlink Uplink configu- Switch-pointSubframe number ration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U UD S U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D DD D D 6 5 ms D S U U U D S U U D

Referring to Table 1, in each subframe of the radio frame, “D” isindicative of a subframe for downlink transmission, “U” is indicative ofa subframe for uplink transmission, and “S” is indicative of a specialsubframe including three types of a DwPTS, GP, and UpPTS. Anuplink-downlink configuration may be classified into 7 types. Thepositions and/or number of downlink subframes, special subframes, anduplink subframe are different in each configuration.

A point of time at which a change is performed from downlink to uplinkor a point of time at which a change is performed from uplink todownlink is called a switching point. The periodicity of the switchingpoint means a cycle in which an uplink subframe and a downlink subframeare changed is identically repeated. Both 5 ms and 10 ms are supportedin the periodicity of a switching point. If the periodicity of aswitching point has a cycle of a 5 ms downlink-uplink switching point,the special subframe S is present in each half frame. If the periodicityof a switching point has a cycle of a 5 ms downlink-uplink switchingpoint, the special subframe S is present in the first half frame only.

In all the configurations, 0 and 5 subframes and a DwPTS are used foronly downlink transmission. An UpPTS and a subframe subsequent to asubframe are always used for uplink transmission.

Such uplink-downlink configurations may be known to both an eNB and UEas system information. An eNB may notify UE of a change of theuplink-downlink allocation state of a radio frame by transmitting onlythe index of uplink-downlink configuration information to the UEwhenever the uplink-downlink configuration information is changed.Furthermore, configuration information is kind of downlink controlinformation and may be transmitted through a Physical Downlink ControlChannel (PDCCH) like other scheduling information. Configurationinformation may be transmitted to all UEs within a cell through abroadcast channel as broadcasting information.

Table 2 below shows a configuration (length of DwPTS/GP/UpPTS) of aspecial subframe.

TABLE 2 Normal cyclic prefix in Extended cyclic prefix in downlinkdownlink UpPTS UpPTS Special Normal Extended Normal Extended subframecyclic cyclic cyclic cyclic config- prefix prefix prefix prefix inuration DwPTS in uplink in uplink DwPTS in uplink in uplink 0  6592 ·T_(s) 2192 · T_(s) 2560 · T_(s)  7680 · T_(s) 2192 · T_(s) 2560 · T_(s)1 19760 · T_(s) 20480 · T_(s) 2 21952 · T_(s) 23040 · T_(s) 3 24144 ·T_(s) 25600 · T_(s) 4 26336 · T_(s)  7680 · T_(s) 5  6592 · T_(s) 4384 ·T_(s) 5120 · T_(s) 20480 · T_(s) 4384 · T_(s) 5120 · T_(s) 6 19760 ·T_(s) 23040 · T_(s) 7 21952 · T_(s) — — — 8 24144 · T_(s) — — —

The structure of a radio frame is only one example. The number ofsubcarriers included in a radio frame or the number of slots included ina subframe and the number of OFDM symbols included in a slot may bechanged in various ways.

FIG. 2 is a diagram illustrating a resource grid for one downlink slotin a wireless communication system to which an embodiment of the presentinvention may be applied.

Referring to FIG. 2, one downlink slot includes a plurality of OFDMsymbols in a time domain. It is described herein that one downlink slotincludes 7 OFDMA symbols and one resource block includes 12 subcarriersfor exemplary purposes only, and the present invention is not limitedthereto.

Each element on the resource grid is referred to as a resource element,and one resource block (RB) includes 12×7 resource elements. The numberof RBs NDL included in a downlink slot depends on a downlinktransmission bandwidth.

The structure of an uplink slot may be the same as that of a downlinkslot.

FIG. 3 shows the structure of a downlink subframe in a wirelesscommunication system to which an embodiment of the present invention maybe applied.

Referring to FIG. 3, a maximum of three OFDM symbols located in a frontportion of a first slot of a subframe correspond to a control region inwhich control channels are allocated, and the remaining OFDM symbolscorrespond to a data region in which a physical downlink shared channel(PDSCH) is allocated. Downlink control channels used in 3GPP LTEinclude, for example, a physical control format indicator channel(PCFICH), a physical downlink control channel (PDCCH), and a physicalhybrid-ARQ indicator channel (PHICH).

A PCFICH is transmitted in the first OFDM symbol of a subframe andcarries information about the number of OFDM symbols (i.e., the size ofa control region) which is used to transmit control channels within thesubframe. A PHICH is a response channel for uplink and carries anacknowledgement (ACK)/not-acknowledgement (NACK) signal for a HybridAutomatic Repeat Request (HARQ). Control information transmitted in aPDCCH is called Downlink Control Information (DCI). DCI includes uplinkresource allocation information, downlink resource allocationinformation, or an uplink transmission (Tx) power control command for aspecific UE group.

A PDCCH may carry information about the resource allocation andtransport format of a downlink shared channel (DL-SCH) (this is alsocalled an “downlink grant”), resource allocation information about anuplink shared channel (UL-SCH) (this is also called a “uplink grant”),paging information on a PCH, system information on a DL-SCH, theresource allocation of a higher layer control message, such as a randomaccess response transmitted on a PDSCH, a set of transmission powercontrol commands for individual UE within specific UE group, and theactivation of a Voice over Internet Protocol (VoIP), etc. A plurality ofPDCCHs may be transmitted within the control region, and UE may monitora plurality of PDCCHs. A PDCCH is transmitted on a single ControlChannel Element (CCE) or an aggregation of some contiguous CCEs. A CCEis a logical allocation unit that is used to provide a PDCCH with acoding rate according to the state of a radio channel. A CCE correspondsto a plurality of resource element groups. The format of a PDCCH and thenumber of available bits of a PDCCH are determined by an associationrelationship between the number of CCEs and a coding rate provided byCCEs.

An eNB determines the format of a PDCCH based on DCI to be transmittedto UE and attaches a Cyclic Redundancy Check (CRC) to controlinformation. A unique identifier (a Radio Network Temporary Identifier(RNTI)) is masked to the CRC depending on the owner or use of a PDCCH.If the PDCCH is a PDCCH for specific UE, an identifier unique to the UE,for example, a Cell-RNTI (C-RNTI) may be masked to the CRC. If the PDCCHis a PDCCH for a paging message, a paging indication identifier, forexample, a Paging-RNTI (P-RNTI) may be masked to the CRC. If the PDCCHis a PDCCH for system information, more specifically, a SystemInformation Block (SIB), a system information identifier, for example, aSystem Information-RNTI (SI-RNTI) may be masked to the CRC. A RandomAccess-RNTI (RA-RNTI) may be masked to the CRC in order to indicate arandom access response which is a response to the transmission of arandom access preamble by UE.

FIG. 4 shows the structure of an uplink subframe in a wirelesscommunication system to which an embodiment of the present invention maybe applied.

Referring to FIG. 4, the uplink subframe may be divided into a controlregion and a data region in a frequency domain. A physical uplinkcontrol channel (PUCCH) carrying uplink control information is allocatedto the control region. A physical uplink shared channel (PUSCH) carryinguser data is allocated to the data region. In order to maintain singlecarrier characteristic, one UE does not send a PUCCH and a PUSCH at thesame time.

A Resource Block (RB) pair is allocated to a PUCCH for one UE within asubframe. RBs belonging to an RB pair occupy different subcarriers ineach of 2 slots. This is called that an RB pair allocated to a PUCCH isfrequency-hopped in a slot boundary.

As more communication devices require greater communication capacity, anecessity of mobile broadband communication which is more improved thanthe existing radio access technology (RAT) has been raised. In addition,the massive MTC (Machine Type Communications) that provides variousservices anytime and anywhere by connecting a plurality of devices andobjects is also one of important issues, which is considered in a nextgeneration communication. Moreover, it has been discussed a design of acommunication system in which a service and/or a UE sensitive toreliability and latency. As such, an introduction of a next generationRAT has been discussed currently, which considers enhanced mobilebroadband communication, massive MTC, Ultra-Reliable and Low LatencyCommunication (URLLC), and the like, and such a technology is referredto as ‘new RAT (NR)’.

Self-Contained Subframe Structure

FIG. 5 illustrates a self-contained subframe structure to which thepresent invention may be applied.

In TDD system, in order to minimize data transmission delay, theself-contained subframe structure as shown in FIG. 5 has been consideredin 5 Generation new RAT. The shaded area in FIG. 5 shows a downlinkcontrol region, and the dark area shows an uplink control region. Inaddition, the area not marked in FIG. 5 may be used for a downlink (DL)data transmission or an uplink (UL) data transmission. In thecharacteristics of such a structure, a DL transmission and a ULtransmission may be sequentially progressed in a subframe, a DL data maybe transmitted and a UL ACK/NACK may be received in a subframe.Consequently, a time required for retransmitting data is reduced when adata transmission error occurs, and owing to this, the delay till thelast data forwarding may be minimized.

As an example of the self-contained subframe structure which may beconfigured/setup in a system operating based on New RAT, the followingat least four subframe types may be considered. Hereinafter, thedurations existed in each of the subframe types are numerated in timesequence.

1) DL control duration+DL data duration+guard period (GP)+UL controlduration

2) DL control duration+DL data duration

3) DL data duration+GP+UL control duration+UL control duration

4) DL data duration+GP+UL control duration

In such a self-contained subframe structure, a time gap is required fora process that an eNB and a UE switch from a transmission mode to areception mode or a process that an eNB and a UE switch from a receptionmode to a transmission mode. For this, a part of OFDM symbols on thetiming switching from DL to UL may be setup as GP, and such a subframetype may be referred to as ‘self-contained SF’.

Analog Beamforming

In Millimeter Wave (mmW) band, a wavelength becomes short and aninstallation of a plurality of antenna elements is available in the samearea. That is, the wavelength in 30 GHz band is 1 cm, and accordingly,an installation of total 100 antenna elements is available in2-dimensional arrangement shape with 0.5 lambda (wavelength) intervalsin 5 by 5 cm panel. Therefore, in mmW band, beamforming (BF) gain isincreased by using a plurality of antenna elements, and accordingly,coverage is increased or throughput becomes higher.

In this case, each antenna element has a Transceiver Unit (TXRU) suchthat it is available to adjust a transmission power and a phase, andindependent beamforming is available for each frequency resource.However, it has a problem that effectiveness is degraded in a costaspect when TXRUs are installed in all of about 100 antenna elements.Accordingly, a method has been considered to map a plurality of antennaelements in a single TXRU and to adjust a direction of beam by an analogphase shifter. Such an analog beamforming technique may make only onebeam direction throughout the entire band, and there is a disadvantagethat frequency selective beamforming is not available.

As a middle form between a Digital BF and an analog BF, B number ofhybrid BF may be considered which is smaller than Q number of antennaelement. In this case, directions of beams that may be transmittedsimultaneously are limited lower than B number; even it is changedaccording to a connection scheme between B number of TXRUs and Q numberof antenna elements.

FIGS. 6 and 7 illustrate a representative connection scheme between aTXRU and an antenna element. More particularly, FIG. 6 exemplifies asub-array partition model, which is a first TXRU virtualization modeloption and FIG. 7 exemplifies a full-connection model, which is a secondTXRU virtualization model option. In FIGS. 6 and 7, TXRU virtualizationmodel represents a relation between an output signal of a TXRU and anoutput signal of an antenna element.

As shown in FIG. 6, in the case of the virtualization model in which aTXRU is connected to a sub-array, an antenna element is connected toonly a single TXRU. Different from this, in the case of thevirtualization model in which a TXRU is connected to all antennaelements, an antenna element is connected to all TXRUs. In thesedrawings, W represents a phase vector which is multiplied by an analogphase shifter. That is, a direction of analog beamforming is determinedby W. Here, mapping between CSI-RS antenna ports and TXRUs may be 1 to 1(1:1) or 1 to many (1:N).

Reference Signal (RS)

In a wireless communication system, a signal may be distorted duringtransmission because data is transmitted through a radio channel. Inorder for a reception end to accurately receive a distorted signal, thedistortion of a received signal needs to be corrected using channelinformation. In order to detect channel information, a method ofdetecting channel information using the degree of the distortion of asignal transmission method and a signal known to both the transmissionside and the reception side when they are transmitted through a channelis mainly used. The aforementioned signal is called a pilot signal orreference signal (RS).

Furthermore recently, when most of mobile communication systems transmita packet, they use a method capable of improving transmission/receptiondata efficiency by adopting multiple transmission antennas and multiplereception antennas instead of using one transmission antenna and onereception antenna used so far. When data is transmitted and receivedusing multiple input/output antennas, a channel state between thetransmission antenna and the reception antenna should be detected inorder to accurately receive the signal. Accordingly, each transmissionantenna should have an individual reference signal.

Ina mobile communication system, an RS may be basically divided into twotypes depending on its purpose. There are an RS having a purpose ofobtaining channel state information and an RS used for datademodulation. The former has a purpose of obtaining, by a UE, to obtainchannel state information in the downlink, and accordingly, acorresponding RS should be transmitted in a wideband, and a UE should becapable of receiving and measuring the RS although the UE does notreceive downlink data in a specific subframe. Furthermore, the former isalso used for radio resources management (RRM) measurement, such ashandover. The latter is an RS transmitted along with correspondingresources when an eNB transmits the downlink. A UE may perform channelestimation by receiving a corresponding RS and thus may demodulate data.The corresponding RS should be transmitted in a region in which data istransmitted.

A downlink RS includes one common RS (CRS) for the acquisition ofinformation about a channel state shared by all of UEs within a cell andmeasurement, such as handover, and a dedicated RS (DRS) used for datademodulation for only a specific UE. Information for demodulation andchannel measurement may be provided using such RSs. That is, the DRS isused only for data demodulation, and the CRS is used for the twopurposes of channel information acquisition and data demodulation.

The reception side (i.e., UE) measures a channel state based on a CRSand feedbacks an indicator related to channel quality, such as a channelquality indicator (CQI), a precoding matrix index (PMI) and/or a rankindicator (RI), back to the transmission side (i.e., an eNB). The CRS isalso called a cell-specific RS. On the other hand, a reference signalrelated to the feedback of channel state information (CSI) may bedefined as a CSI-RS.

In 3GPP LTE(-A) system, it is defined that a UE reports CSI to a BS.Here, the CSI is commonly called for the information that may representa quality of a radio channel (or also referred to as a link) establishedbetween a UE and an antenna port. For example, the CSI may correspond toa rank indicator (RI), a precoding matrix indicator (PMI), and/or achannel quality indicator (CQI), and the like. Here, RI represents rankinformation of a channel, and this may mean the number of streams that aUE receives through the same time-frequency resource. Since RI isdetermined with being dependent upon long-term fading of a channel, theRI is fed back from a UE to a BS with a period longer than CQI,generally. PMI is a value that reflects a channel space property, andrepresents a precoding index that a UE prefers based on a metric such asSINR. CQI is a value that represents signal strength, and means areception SINR that is obtainable when a BS uses the PMI, generally.

In 3GPP LTE(-A) system, a BS may setup a plurality of CSI processes to aUE, and may receive CSI report for each process. Here, the CSI processmay include CSI-RS for signal quality measurement from a BS andCSI-interference measurement (CSI-IM) resource for interferencemeasurement.

The DRS may be transmitted through resource elements if datademodulation on a PDSCH is required. A UE may receive information aboutwhether a DRS is present through a higher layer, and the DRS is validonly in the case that a corresponding PDSCH has been mapped. The DRS mayalso be called a UE-specific RS or Demodulation RS (DMRS).

FIGS. 8A and 8B illustrate reference signal patterns mapped to downlinkresource block pairs in a wireless communication system to which thepresent invention may be applied.

Referring to FIGS. 8A and 8B, a downlink resource block pair, a unit inwhich a reference signal is mapped may be represented in the form of onesubframe in a time domain X 12 subcarriers in a frequency domain. Thatis, in a time axis (an x axis), one resource block pair has a length of14 OFDM symbols in the case of a normal cyclic prefix (CP) (in FIG.7(a)) and has a length of 12 OFDM symbols in the case of an extendedcyclic prefix (CP) (FIG. 7(b)). In the resource block lattice, resourceelements (REs) indicated by ‘0’, ‘1’, ‘2’, and ‘3’ mean the locations ofthe CRSs of antenna port indices ‘0’, ‘1’, ‘2’, and ‘3’, respectively,and REs indicated by ‘D’ mean the location of a DRS.

In the case that an eNB uses a single transmission antenna, referencesignals for a single antenna port are arrayed.

In the case that an eNB uses two transmission antennas, referencesignals for two transmission antenna ports are arrayed using a timedivision multiplexing (TDM) scheme and/or a frequency divisionmultiplexing (FDM) scheme. That is, different time resources and/ordifferent frequency resources are allocated in order to distinguishbetween reference signals for two antenna ports.

Furthermore, in the case that an eNB uses four transmission antennas,reference signals for four transmission antenna ports are arrayed usingthe TDM and/or FDM schemes. Channel information measured by thereception side (i.e., UE) of a downlink signal may be used to demodulatedata transmitted using a transmission scheme, such as singletransmission antenna transmission, transmission diversity, closed-loopspatial multiplexing, open-loop spatial multiplexing or a multi-userMIMO antenna.

In the case that a multi-input multi-output antenna is supported, when aRS is transmitted by a specific antenna port, the RS is transmitted inthe locations of resource elements specified depending on a pattern ofthe RS and is not transmitted in the locations of resource elementsspecified for other antenna ports. That is, RSs between differentantennas do not overlap.

In an LTE-A system, that is, an evolved and developed form of the LTEsystem, the design is necessary to support a maximum of eighttransmission antennas in the downlink of an eNB. Accordingly, RSs forthe maximum of eight transmission antennas must be also supported. Inthe LTE system, only downlink RSs for a maximum of four antenna portshas been defined. Accordingly, in the case that an eNB has four to amaximum of eight downlink transmission antennas in the LTE-A system, RSsfor these antenna ports must be additionally defined and designed.Regarding the RSs for the maximum of eight transmission antenna ports,both of the aforementioned RS for channel measurement and theaforementioned RS for data demodulation should be designed.

One of important factors considered in designing an LTE-A system isbackward compatibility, that is, that an LTE UE should operate properlyalso in the LTE-A system, which should be supported by the system. Froman RS transmission aspect, in the time-frequency domain in which a CRSdefined in LTE is transmitted in a full band every subframe, RSs for amaximum of eight transmission antenna ports should be additionallydefined. In the LTE-A system, if an RS pattern for a maximum of eighttransmission antennas is added in a full band every subframe using thesame method as the CRS of the existing LTE, RS overhead is excessivelyincreased.

Accordingly, the RS newly designed in the LTE-A system is basicallydivided into two types, which include an RS having a channel measurementpurpose for the selection of MCS or a PMI (channel state information-RS,channel state indication-RS (CSI-RS), etc.) and an RS for thedemodulation of data transmitted through eight transmission antennas(data demodulation-RS (DM-RS)).

The CSI-RS for the channel measurement purpose is characterized in thatit is designed for a purpose focused on channel measurement unlike theexisting CRS used for purposes of measurement, such as channelmeasurement and handover, and for data demodulation. Furthermore, theCSI-RS may also be used for a purpose of measurement, such as handover.The CSI-RS does not need to be transmitted every subframe unlike the CRSbecause it is transmitted for a purpose of obtaining information about achannel state. In order to reduce overhead of a CSI-RS, the CSI-RS isintermittently transmitted on the time axis.

In the LTE-A system, a maximum of eight transmission antennas aresupported in the downlink of an eNB. In the LTE-A system, in the casethat RSs for a maximum of eight transmission antennas are transmitted ina full band in every subframe using the same method as the CRS in theexisting LTE, RS overhead is excessively increased. Accordingly, in theLTE-A system, an RS has been separated into the CSI-RS of the CSImeasurement purpose of the selection of MCS or a PMI and the DM-RS fordata demodulation, and thus the two RSs have been added. The CSI-RS mayalso be used for a purpose, such as RRM measurement, but has beendesigned for a main purpose of the acquisition of CSI. The CSI-RS doesnot need to be transmitted every subframe because it is not used fordata demodulation. Accordingly, in order to reduce overhead of theCSI-RS, the CSI-RS is intermittently transmitted on the time axis. Thatis, the CSI-RS has a period corresponding to a multiple of the integerof one subframe and may be periodically transmitted or transmitted in aspecific transmission pattern. In this case, the period or pattern inwhich the CSI-RS is transmitted may be set by an eNB.

In order to measure a CSI-RS, a UE should be aware of information aboutthe transmission subframe index of the CSI-RS for each CSI-RS antennaport of a cell to which the UE belongs, the location of a CSI-RSresource element (RE) time-frequency within a transmission subframe, anda CSI-RS sequence.

In the LTE-A system, an eNB has to transmit a CSI-RS for each of amaximum of eight antenna ports. Resources used for the CSI-RStransmission of different antenna ports must be orthogonal. When one eNBtransmits CSI-RSs for different antenna ports, it may orthogonallyallocate the resources according to the FDM/TDM scheme by mapping theCSI-RSs for the respective antenna ports to different REs.Alternatively, the CSI-RSs for different antenna ports may betransmitted according to the CDM scheme for mapping the CSI-RSs topieces of code orthogonal to each other.

When an eNB notifies a UE belonging to the eNB of information on aCSI-RS, first, the eNB should notify the UE of information about atime-frequency in which a CSI-RS for each antenna port is mapped.Specifically, the information includes subframe numbers in which theCSI-RS is transmitted or a period in which the CSI-RS is transmitted, asubframe offset in which the CSI-RS is transmitted, an OFDM symbolnumber in which the CSI-RS RE of a specific antenna is transmitted,frequency spacing, and the offset or shift value of an RE in thefrequency axis.

A CSI-RS is transmitted through one, two, four or eight antenna ports.Antenna ports used in this case are p=15, p=15, 16, p=15, . . . , 18,and p=15, . . . , 22, respectively. A CSI-RS may be defined only for asubcarrier interval Δf=15 kHz.

RS virtualization

In mmW band, a PDSCH transmission is available only to a single analogbeam direction on a time by analog beamforming. As a result, an eNB isable to transmit data only to a small number of UEs in a specificdirection. Accordingly, on occasion demands, analog beam direction isdifferently configured for each antenna port, and a data transmissionmay be performed to a plurality of UEs in several analog beam directionssimultaneously.

Hereinafter, four sub-arrays are formed by dividing 256 antenna elementsinto four equal parts, and an exemplary structure in which a TXRU isconnected to each sub-array shown in FIGS. 9A through 9C is describedmainly.

FIGS. 9A through 9C is a diagram illustrating a service area for eachTXRU.

When each sub-array includes total 64 (8×8) antenna elements in2-dimensional array shape, a region corresponding to a horizontal anglearea of 15 degrees and a vertical angle area of 15 degrees may becovered by specific analog beamforming. That is, a region in which aneNB is needed to serve is divided into a plurality of areas, and eacharea is served at a time. In the following description, it is assumedthat CSI-RS antenna port and TXRU are mapped in 1-to-1 manner.Accordingly, an antenna port and a TXRU may have the same meaning in thefollowing description.

As shown in an example of FIG. 9A, in the case that all TXRUs (antennaport, sub-array) have the same analog beamforming direction, thethroughput of the corresponding region may be increased by forming adigital beam having higher resolution. In addition, the throughput ofthe corresponding region may be increased by increasing rank oftransmission data to the corresponding region.

As shown in FIG. 9B, in the case that each TXRU (antenna port,sub-array) has different analog beamforming direction, a simultaneousdata transmission becomes available in a corresponding subframe (SF) toUEs distributed in wider area. For example, among four antenna ports,two of them are used for a PDSCH transmission to UE1 in area 1 and theremaining two of them are used for a PDSCH transmission to UE2 in area2.

FIG. 9B shows an example that PDSCH 1 transmitted to UE1 and PDSCH 2transmitted to UE2 are Spatial Division Multiplexed (SDM). Differentfrom this, FIG. 9C shows an example that PDSCH 1 transmitted to UE1 andPDSCH 2 transmitted to UE2 may be transmitted by being FrequencyDivision Multiplexed (FDM).

Between the scheme of serving an area by using all antenna ports and thescheme of serving several areas simultaneously by dividing antennaports, in order to maximize cell throughput, a preferred scheme may bechanged depending on a RANK and an MCS served to a UE. In addition, apreferred scheme may also be changed depending on an amount of data tobe transmitted to each UE.

An eNB calculates cell throughput or scheduling metric that may beobtained when serving an area by using all antenna ports, and calculatescell throughput or scheduling metric that may be obtained when servingtwo areas by dividing antenna ports. The eNB compares the cellthroughput or the scheduling metric that may be obtained through eachscheme, and selects a final transmission scheme. Consequently, thenumber of antenna ports participated in a PDSCH transmission is changedfor each SF (SF-by-SF). In order for an eNB to calculate a transmissionMCS of a PDSCH according to the number of antenna ports and reflect itto scheduling algorithm, a CSI feedback from a UE proper to it may berequested.

Beam reference signal (BRS) and Beam refinement reference signal (BRRS)

BRSs may be transmitted in at least one antenna port p={0, 1, . . . ,7}. BRS sequence r_(l)(m) may be defined as Equation 1 below.

$\begin{matrix}{{{r_{l}(m)} = {{\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {2m} \right)}}} \right)} + {j\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {{2m} + 1} \right)}}} \right)}}},\mspace{79mu}{m = 0},1,\ldots\mspace{14mu},{{8 \cdot \left( {N_{RB}^{{m\;{ax}},{DL}} - 18} \right)} - 1}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In Equation 1,

=0, 1, . . . , 13 may represents an OFDM symbol number. In addition,c(i) represents a pseudo-random sequence generator, and may beinitialized by Equation 2 on a starting point of each OFDM symbol.

[Equation 2]

C_(init) = 2¹⁰ ⋅ (7 ⋅ (n_(s) + 1) + l^(′) + 1) ⋅ (2 ⋅ N_(ID)^(cell) + 1) + 2 ⋅ N_(ID)^(cell) + 1$n_{s} = \left\lfloor \frac{l}{7} \right\rfloor$ l^(′) = l mod 7

BRRS may be transmitted in maximum eight antenna ports p=600, . . . ,607. A transmission and a reception of BRRS may be dynamically scheduledin a downlink resource allocation in xPDCCH.

BRRS sequence r_(l,n) _(s) (m) may be defined as Equation 3 below.

$\begin{matrix}{{{r_{l,n_{s}}(m)} = {{\frac{1}{\sqrt{2}}\left( {1 - {2{c\left( {2m} \right)}}} \right)} + {j\frac{1}{\sqrt{2}}\left( {1 - {2{c\left( {{2m} + 1} \right)}}} \right)}}},\mspace{79mu}{m = 0},1,\ldots\mspace{14mu},{\left\lfloor {\frac{3}{8}N_{RB}^{{{ma}\; x},{DL}}} \right\rfloor - 1}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

In Equation 3, ns represents a slot number in a radio frame, lrepresents an OFDM symbol number in the slot, and c(n) represents apseudo-random sequence. The pseudo-random sequence generator may beinitialized by Equation 4 on a starting point of each OFDM symbol.

c _(init)=2¹⁰(7( n _(s)+1)+l+1)(2N _(ID) ^(BRRS)+1)+2N _(ID) ^(BRRS)+1

n _(s) =n _(s) mod 20  [Equation 4]

In Equation 4, N_(ID) ^(BRRS) may be set to a UE through Radio ResourceControl (RRC) signaling.

BRS may be transmitted in every subframe, and may be transmitted indifferent analog beam directions for each port. Such a BRS may be usedfor an eNB to determine an approximate beam direction for a UE. When anapproximate beam direction for a UE is determined based on BRS, an eNBmay transmit BRRS for each of more accurate/minute analog beamdirections within the determined analog beam direction range, and maydetermine more accurate analog beam direction.

As such, the name for the reference signal used for determining ananalog beam direction for a UE is not limited to the BRS or the BRRSdescribed above, and it is apparent that the name may be substitutedby/referred to various reference signals that are usable for performingthe same function. For example, the BRS may be substituted by/referredto primary/first CSI-RS, Primary synchronization signal/sequence (PSS),Secondary synchronization signal/sequence (SSS), SynchronizationSignal/Sequence (SS) block, NR-PSS, and/or NR-SSS, and the BRRS may besubstituted by/referred to secondary/second CSI-RS.

DL Phase noise compensation reference signal (DL PCRS)

A PCRS associated with xPDSCH may be transmitted in antenna port P=60 orP=61 as it is signaled in a DCI format. The PCRS is existed only in thecase that xPDSCH transmission is associated with a corresponding antennaport, and the PCRS in this case may be a valid reference for phase noisecompensation. The PCRS may be transmitted only in physical resourceblocks and symbols to which corresponding xPDSCH is mapped. The PCRS maybe the same in all symbols that correspond to xPDSCH allocation.

For both of the antenna ports P=60, 61, PCRS sequence r(m) may bedefined as Equation 5 below.

$\begin{matrix}{{{r(m)} = {{\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {2m} \right)}}} \right)} + {j\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {{2m} + 1} \right)}}} \right)}}},\mspace{79mu}{m = 0},1,\ldots\mspace{14mu},{\left\lfloor {N_{RB}^{{{ma}\; x},{DL}}/4} \right\rfloor - 1}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

In Equation 5, c(i) represents pseudo-random sequence. The pseudo-randomsequence generator may be initialized by Equation 6 on a starting pointof each subframe.

c _(init)=(└n _(s)/2┘+1)·(2n _(ID) ^((n) ^(SCID) ⁾+1)·2¹⁶ +n_(SCID)  [Equation 6]

In Equation 6, n_(ID) ^((f)) may be determined as below when i=0, 1.

-   -   In the case that a value for n_(ID) ^(PCRS,i) is not provided by        a higher layer, n_(ID) ^((t))=N_(ID) ^(cell)    -   Otherwise, n_(ID) ^((t))=n_(ID) ^(PCRS,i)

A value of n_SCID may be set to 0, unless it is particularly determined.In xPDSCH transmission, n_SCID may be provided by a DCI formationassociated with xPDSCH transmission.

Quasi Co-Located (QCL) Between Antenna Ports

In the present invention, when a UE receives data (e.g., PDSCH), ascheme is considered for demodulating the data using a UE-specific RSlike a specific DMRS. Since such a DMRS is transmitted together withscheduled RB(s) of the corresponding PDSCH only and during only a timeduration in which a scheduled PDSCH is transmitted, there may be arestriction in reception performance in performing channel estimationonly with the corresponding DMRS. For example, for performing channelestimation, an estimation value of major large-scale parameter/property(LSP) of a radio channel is required, and DMRS density may be in shortto obtain only the DMRS existed in time/frequency domain through whichthe scheduled PDSCH is transmitted. Accordingly, in order to supportsuch a UE implementation, in LTE-A, the following quasi co-locationsignaling/assumption/behavior between RS ports is defined, andaccordingly this, the methods of configuring/operating a UE aresupported.

Quasi co-located and quasi co-location (QC/QCL) may be defined asfollows.

If two antenna ports have a QC/QCL relationship (or subjected toQC/QCL), UE may assume that the large-scale property of a signaltransferred through one antenna port may be inferred from a signaltransferred through the other antenna port. In this case, thelarge-scale property includes one or more of Delay spread, Dopplerspread, Frequency shift, Average received power, and Received timing.

Furthermore, the following may be defined. Assuming that two antennaports have a QC/QCL relation (or subjected to QC/QCL), UE may assumethat the large-scale property of a channel of which one symbol istransferred through one antenna port may be inferred from a wirelesschannel of which one symbol is transferred through the other antennaport. In this case, the large-scale property includes one or more ofDelay spread, Doppler spread, Doppler shift, Average gain, and Averagedelay.

That is, if two antenna ports have a QC/QCL relation (or subjected toQC/QCL), it means that the large-scale property of a wireless channelfrom one antenna port is the same as the large-scale property of awireless channel from the other antenna port. Assuming that a pluralityof antenna ports in which an RS is transmitted is taken intoconsideration, if antenna ports on which two types of different RSs aretransmitted have a QCL relation, the large-scale property of a wirelesschannel from one antenna port may be replaced with the large-scaleproperty of a wireless channel from the other antenna port.

In this specification, the QC/QCL-related definitions are notdistinguished. That is, the QC/QCL concept may comply with one of thedefinitions. In a similar other form, the QC/QCL concept definition maybe changed in a form in which antenna ports having an established QC/QCLassumption may be assumed to be transmitted at the same location (i.e.,co-location) (e.g., UE may assume antenna ports to be antenna portstransmitted at the same transmission point). The spirit of the presentinvention includes such similar modifications. In an embodiment of thepresent invention, the QC/QCL-related definitions are interchangeablyused, for convenience of description.

In accordance with the concept of the QC/QCL, UE may not assume the samelarge-scale property between wireless channels from correspondingantenna ports with respect to non-QC/QCL antenna ports. That is, in thiscase, UE may perform independent processing on timing acquisition andtracking, frequency offset estimation and compensation, delayestimation, and Doppler estimation for each configured non-QC/QCLantenna port.

There are advantages in that UE may perform the following operationsbetween antenna ports capable of an assuming QC/QCL:

-   -   With respect to the Delay spread and Doppler spread, UE may        identically apply the results of a power-delay profile, Delay        spread and Doppler spectrum, and Doppler spread estimation for a        wireless channel from any one antenna port to a Wiener filter        which is used upon channel estimation for a wireless channel        from other antenna ports.    -   With respect to the Frequency shift and received timing, UE may        perform time and frequency synchronization on any one antenna        port and then apply the same synchronization to the demodulation        of other antenna ports.    -   With respect to the Average received power, UE may average        reference signal received power (RSRP) measurement for two or        more antenna ports.

For example, if a DMRS antenna port for downlink data channeldemodulation has been subjected to QC/QCL with the CRS antenna port of aserving cell, UE may apply the large-scale property of a wirelesschannel estimated from its own CRS antenna port upon channel estimationthrough the corresponding DMRS antenna port, in the same manner, therebyimproving reception performance of a DMRS-based downlink data channel.

The reason for this is that an estimation value regarding a large-scaleproperty may be more stably obtained from a CRS because the CRS is areference signal that is broadcasted with relatively high density everysubframe and in a full bandwidth. In contrast, a DMRS is transmitted ina UE-specific manner with respect to a specific scheduled RB, and theprecoding matrix of a precoding resource block group (PRG) unit that isused by an eNB for transmission may be changed. Thus, a valid channelreceived by UE may be changed in a PRG unit. Accordingly, although aplurality of PRGs has been scheduled in the UE, performancedeterioration may occur when the DMRS is used to estimate thelarge-scale property of a wireless channel over a wide band.Furthermore, a CSI-RS may also have a transmission cycle of severalseveral tens of ms, and each resource block has also low density of 1resource element for each antenna port in average. Accordingly, theCSI-RS may experience performance deterioration if it is used toestimate the large-scale property of a wireless channel.

That is, UE may perform the detection/reception, channel estimation, andchannel state report of a downlink reference signal through a QC/QCLassumption between antenna ports.

Meanwhile, a UE may assume that antenna ports 0-3 of a serving cell andan antenna port for PSS/SSS are in QCL relation for Doppler shift andaverage delay.

PDSCH resource mapping parameters

A UE configured with transmission mode 10 for a given serving cell maybe configured with up to four parameter sets by higher layer signalingin order to decode a PDSCH according to detected PDCCH/EPDCCH that hasDCI format 2D which is intended for the UE and the given serving cell.

In order for the UE to determine PDSCH RE mapping and to determine PDSCHantenna port QCL when the UE is configured with Type B QCL type, the UEuses the parameter configured according to ‘PDSCH RE Mapping andQuasi-Co-Location indicator’ field value, which is described in belowTable 3, in the detected PDCCH/EPDCCH that has DCI format 2D.

In the case of a PDSCH that has no corresponding PDCCH/EPDCCH, the UEuses the parameter set indicated in the PDCCH/EPDCCH that has DCI format2D corresponding to SPS activation which is associated to determinePDSCH RE mapping and PDSCH antenna port QCL.

TABLE 3 Value of ‘PDSCH RE Mapping and Quasi- Co-Location Indicator’field Description ‘00’ Parameter set 1 configured by higher layers ‘01’Parameter set 2 configured by higher layers ‘10’ Parameter set 3configured by higher layers ‘11’ Parameter set 4 configured by higherlayers

The following parameters for determining PDSCH RE mapping and PDSCHantenna port QCL are configured through higher layer signaling for eachparameter set.

-   -   crs-PortsCount-r11    -   crs-FreqShift-r11    -   mbsfn-SubframeConfigList-r11    -   csi-RS-ConfigZPld-r11    -   pdsch-Start-r11    -   qcl-CSI-RS-ConfigNZPld-r11    -   zeroTxPowerCSI-RS2-r12 (when a UE is configured with higher        layer parameter CSI-Reporting-Type for a TDD serving cell)

In the case that a PDSCH is decoded according to detected PDCCH/EPDCCHhaving DCI format 1A that has CRC scrambled with C-RNTI intended for ause of a UE and a given serving cell, and a UE is configured with Type BQCL type for PDSCH transmission in antenna port 7, in order to determinePDSCH RE mapping and PDSCH antenna port QCL, a UE to which transmissionmode 10 for a given serving cell is set should use parameter set 1 inTable 3.

In order to decode a PDSCH corresponding to PDCCH/EPDCCH having DCIformat 1A that has CRC scrambled with SPS C-RNTI and PDSCH withoutcorresponding PDCCH/EPDCCH associated with SPS activation indicated byPDCCH/EPDCCH having DCI format 1A, a UE to which transmission mode 10for a given serving cell is set should use parameter set 1 in Table 3 inorder to determine PDSCH RE mapping and PDSCH antenna port QCL.

In order to decode a PDSCH according to detected PDCCH/EPDCCH having DCIformat 1A for a UE in a given serving cell, and to transmit a PDSCH inantenna ports 0-3, a UE set to transmission mode 10 for a given servingcell should determine PDSCH RE mapping using the lower indexedzero-power CSI-RS.

Antenna port QCL for PDSCH

A UE configured with transmission modes 8-10 for a serving cell mayassume that antenna ports 7-14 for the serving cell is in QCL for agiven subframe for delay spread, Doppler spread, Doppler shift, averagegain and average delay.

A UE configured with transmission modes 1-10 for a serving cell mayassume that antenna ports 0-3, 5, 7-30 for the serving cell is in QCLfor Doppler shift, Doppler spread, average delay and delay spread.

A UE configured with transmission mode 10 for a serving cell isconfigured with one of two QCL types for the serving cell by higherlayer parameter QCL operation in order to decode a PDSCH according to atransmission scheme in relation to antenna ports 7-14.

-   -   Type A: For a UE, antenna ports 0-3, 7-30 of a serving cell is        in QCL for delay spread, Doppler spread, Doppler shift and        average delay.    -   Type B: For a UE, antenna ports 15-30 that corresponds to a        CSI-RS resource configuration identified by higher layer        parameter qcl-CSI-RS-ConfigNZPld-r11 and antenna ports 7-14        associated with a PDSCH is in QCL for Doppler shift, Doppler        spread, average delay and delay spread.

In the case of LAA Scell, a UE does not expect that it is configuredwith QCL type B.

Channel-State Information (CSI)—Reference Signal (CSI-RS) definition

With respect to a serving cell and a UE that are configured withtransmission mode 9 and not configured with higher layer parametereMIMO-Type, the UE may be configured with a single CSI-RS resourceconfiguration.

In addition, with respect to a serving cell and a UE that are configuredwith transmission mode 9, configured with higher layer parametereMIMO-Type and of which eMIMO-Type is CLASS A, the UE may be configuredwith a single CSI-RS resource configuration.

With respect to a serving cell and a UE that are configured withtransmission mode 9, configured with higher layer parameter eMIMO-Typeand of which eMIMO-Type is CLASS B, the UE may be configured with one ormore CSI-RS resource configurations.

With respect to a serving cell and a UE that are configured withtransmission mode 10, the UE may be configured with one or more CSI-RSresource configuration(s). The following parameters that the UE assumesnon-zero transmission power for a CSI-RS is configured through higherlayer signaling for each CSI-RS resource configuration:

-   -   CSI-RS resource configuration identity when a UE is configured        with transmission mode 10    -   The number of CSI-RS ports    -   CSI RS configuration    -   CSI RS subframe configuration ICSI-RS    -   UE assumption for a reference PDSCH transmission power Pc for        CSI feedback, when a UE is configured with transmission mode 9    -   UE assumption for a reference PDSCH transmission power Pc for        CSI feedback for each CSI process, when a UE is configured with        transmission mode 10.

In the case that CSI subframe sets CCSI,0 and CCS,1 are configured byhigher layer signaling for a single CSI process, Pc is configured foreach of the CSI subframe sets of the corresponding CSI process.

-   -   Pseudo-random sequence generator parameter nID    -   CDM type parameter, when a UE is configured with higher layer        parameter eMIMO-Type and the eMIMO-Type is set to ‘CLASS A’.    -   Higher layer parameter qcl-CRS-Info-r11CRS, when a UE is        configured with transmission mode 10, UE assumption of CRS        antenna port that has the following parameters and CSI-RS        antenna ports:    -   qcl-Scramblingldentity-r11.    -   crs-PortsCount-r11.    -   mbsfn-SubframeConfigList-r11.

Pc is an assumed ratio of PDSCH EPRE for CSI-RS EPRE when a UE derivesCSI feedback and takes a value in a range of [−8, 15] dB with 1 dB stepsize. Here, the PDSCH EPRE corresponds to symbol number for a ratio ofthe PDSCH EPRE with respect to cell-specific RS EPRE.

A UE does not expect configuration of CSI-RS and PMCH in the samesubframe of a serving cell.

With respect to frame structure type 2 serving cell and 4 CRS ports, aUE does not expect to receive CSI-RS configuration index belonged to set[20 −31] for a normal CP case or set [16 −27] for an extended CP case.

A UE may assume that CSI-RS antenna port of CSI-RS resourceconfiguration is in QCL for delay spread, Doppler spread, Doppler shift,average gain and average delay.

A UE configured with transmission mode 10 and QCL type B may assume thatantenna ports 0 to 3 associated with qc-CRS-Info-r11 corresponding toCSI-RS resource configuration and antenna ports 15 to 30 correspondingto CSI-RS resource configuration are in QCL for Doppler shift andDoppler spread.

A UE configured with transmission 10, configured with higher layerparameter eMIMO-Type and the eMIMO-Type is set to ‘class B’, in whichthe number of configured CSI resources is more than one for a single CSIprocess and having QCL type B does not expect to receive CSI-RS resourceconfiguration for a CSI process that has different value of higher layerparameter qc-CRS-Info-r11.

BL/CE UE configured with CEModeA or CEModeB does not expect that it isconfigured with non-zero transmission power CSI-RS.

CSI Reporting Method

With an introduction of Full Dimension (FD)-MIMO (or may also bereferred to as Massive-MIMO, enhanced-MIMO, Large-Scale Antenna System,Very Large MIMO, Hyper-MIMO, etc.), an eNB may increase throughput of asystem by performing D-beamforming and the like using N (N>>1) antennaports (or corresponds to “element” according to specific port-to-elementvirtualization, and hereinafter, commonly referred to as “port” for theconvenience of description).

Currently, 3GPP Rel-13 defines CSI-RS operation (or CSI reportingoperation, each CSI process may be associated with a single CSI-RSresource and a single CSI-IM resource) of non-precoded scheme defined asClass A and CSI-RS operation (or CSI reporting operation, each CSIprocess may be associated with one or more CSI-RS resources and one ormore CSI-IM resources) of beamformed scheme defined as Class B.

In the case of Class A, in the FD MIMO system, an eNB may configureseveral CSI-RS resources to a UE in a single CSI process. A UE mergeseach of CSI-RS resources configured in a single CSI process into asingle large CSI-RS resource, not regarding it as an independentchannel, and feedbacks by calculating/obtaining CSI from thecorresponding resource. For example, in the case that an eNB configuresthree 4-port CSI-RS resources to a UE in a single CSI process, the UEmerges the configured three 4-port CSI-RS resources and assumes it as asingle 12-port CSI-RS resource. The UE feedbacks bycalculating/obtaining CSI using 12-port PMI from the correspondingresource.

Even in the case of Class B, in the FD MIMO system, an eNB may configureseveral CSI-RS resources to a UE in a single CSI process. For example,in a single CSI process, an eNB may configure eight 4-port CSI-RSresources to a UE. Different virtualizations are applied to therespective eight 4-port CSI-RS, and different beamformings with eachother may be applied. For example, assuming the case that verticalbeamforming is applied with zenith angle of 100 degrees to a firstCSI-RS, vertical beamforming may be applied to second to eighth CSI-RSswith zenith angle difference of 5 degrees, and as a result, verticalbeamforming may be applied to the eighth CSI-RS with zenith angle of 135degrees.

In this case, the UE assumes each of the configured CSI-RS resources asan independent channel, and selects one of the configured CSI-RSresources, and then feedbacks/reports by calculating/obtaining CSI basedon the selected resource. That is, a UE may select a CSI-RS resource ofwhich channel is robust among the configured eight 4-port CSI-RSresources, and calculate CSI based on the selected CSI-RS resource, andthen report it to the eNB. In this case, the UE may report the selectedCSI-RS resource through CSI-RS Resource Index (CRI) value. For example,in the case that the first CSI-RS resource channel is the strongest, theUE may set the CSI value to ‘O’ and report it to the eNB.

In order to represent the technical features described above, in Class BCSI process, the following variables may be defined. K may mean thenumber of CSI-RS resources existed in the CSI process, and Nk may meanthe number of CSI-RS resources of the kth CSI-RS resource. For example,a UE is configured with eight 4-port CSI-RS resources, K is 8 and Nk is4 regardless of k value.

In current Rel-13, CRI indicates a specific CSI-RS resource only, but afuture CRI may be further materialized to indicate a specific portcombination. For example, it may be further materialized that CRIindicates a single CSI-RS resource selected among eight CSI-RS resourcesin a CSI process, and indicates that an additionally selected CSI-RSresource is constructed by a combination of ports #15 and #16. At thistime, assuming that the CRI may indicate a combination of ports #15 and#16 or ports #17 and #18 for each CSI-RS resource, the CRI may be set asone of 16 (=2{circumflex over ( )}4) values.

That is, the case of being configured with CRI=0 indicates a combinationof ports #15 and #16 of the first CSI-RS resource, the case of beingconfigured with CRI=1 indicates a combination of ports #17 and #18 ofthe first CSI-RS resource, the case of being configured with CRI=2indicates a combination of ports #15 and #16 of the second CSI-RSresource, the case of being configured with CRI=3 indicates acombination of ports #17 and #18 of the second CSI-RS resource, and insuch schemes, each of the combinations of CSI-RSs may be indicatedaccording to an ascending order of CRI values. In addition, finally, itmay be identified that the case of being configured with CRI=15indicates a combination of ports #17 and #18 of the last eighth CSI-RSresource.

In the case of Class A, a UE measures N antenna ports, and selectsN-port precoder by using it, and then reports the related CSI (PMI, CQI,RI, etc.) to an eNB. However, as N increases, the CSI-RS for a channelmeasurement of a UE needs to be also increased, and the related codebooksize is also increased, and consequently, feedback overhead is alsoincreased.

On the other hand, in the case of Class B, the number of CSI-RS ports isin relation to a maximum rank of a UE, rather than the number of antennaports of an eNB, and accordingly, there is an advantage that the CSI-RSports may be used without big increase of the number of CRI-RSs even inthe case that the number of antenna ports is increased. However, a beamselection needs to be performed in an eNB, and accordingly, there is adisadvantage that the robustness of beamforming may be degraded in theenvironment that mobility of a UE is high and a beam of an eNB isnarrow.

In order to compensate the disadvantage of the two techniques and tomaximize the advantage, it may be considered the hybrid CSI-RS basedscheme (or CSI reporting scheme) that uses a combination of Class A andClass B.

Assumptions Independent of Physical Channel

A UE should not assume that two antenna ports are in QCL unlessotherwise specified.

A UE may assume that antenna ports 0 to 3 for a serving cell is in QCLfor delay spread, Doppler spread, Doppler shift, average gain andaverage delay.

For the purpose of discovery signal-based measurement, a UE should notassume that there is another signal or physical channel except thediscovery signal.

In the case that a UE supports discoverySignalsnDeactSCell-r12, the UEis configured by discovery signal-based RRM measurement in a carrierfrequency applicable to a secondary cell in the same carrier frequency,the secondary cell is inactivated, and the UE is not configured byhigher layer in order to receive MBMS in the secondary cell, except adiscovery signal transmission, it is assumed that PSS, SSS, PhysicalBroadcast Channel (PBCH), CRS, PCFICH, PDSCH, PDCCH, EPDCCH, PHICH, DMRSand CSI-RS are not transmitted by the corresponding secondary cell untilthe subframe in which an activation command is received for thesecondary cell.

QCL assumption and signaling method for new RAT

The UE performing the QCL operation, in the case that the UE configuredwith QCL Type B, may use LSPs estimated from a specific QCLed CSI-RSresource indicated a scheduling DCI in order to be assisted with channelestimation of a DMRS transmitted together with scheduled PDSCH. However,in the New RAT (NR) environment considered in the present invention,aperiodic CSI-RS transmission scheme is considered in the aspect thatthe transmission of CSI-RS itself is transmitted only when it isrequired departing from the conventional periodic scheme, andaccordingly, there is a problem that the RS density for being utilizedas CSI-RS for QCL assumption becomes in short significantly incomparison with the conventional system. Accordingly, hereinafter, it isproposed embodiments of various QCL operations considering aperiodicCSI-RS transmission scheme in such NR environment. Before theproposition, QCL parameters that may be defined in the NR environmentwill be described. However, the following QCL parameters are not limitedto the NR environment, but may be applied to various wirelesscommunication systems.

1. QCL parameter

As QCL parameters considered (in the NR environment), one of thefollowings may be defined/configured.

-   -   Delay spread    -   Doppler spread    -   Doppler shift    -   Average gain    -   Average delay    -   Average angle (AA):    -   Angular spread (AS)

In the NR environment, when the analog beamforming is applied to a UEside, a new type of QCL property for an arrival angle needs to beconsidered, and accordingly, the parameters in relation to a receptionbeam such as the AA and the AS may be defined as new type of QCLparameters.

Between antenna ports in which QCL is guaranteed in the AA aspect, QCLassumption for a reception beam direction (and/or reception beamwidth/sweeping degree) is available. For example, a UE is available toreceive a transmission signal by setting a reception beam direction(and/or reception beam width/sweeping degree) of a transmission signalfrom other antenna port(s) in the same way as the AA estimated fromspecific antenna port(s) and in the similar way (in relation to this).When a UE operates as such, a reception performance may be guaranteedhigher than a specific level. Such an AA may also be replaced by a term“(Almost) Dominant arrival angle” and the like, for example.

Consequently, the QCL assumption in the AA aspect, when assuming thatthere is a specific dominant (arrival) angle ‘S’ of a signal measuredfrom a specific antenna port, it may be interpreted that the specificdominant (arrival) angle of a signal measured from other antenna port,which is QCL assumed (or has QCL relation) with this, is “almost” thesame as/similar to the ‘S’. That is, a receiver may in which QCLassumption is available may utilize/apply the AA estimated from thespecific indicated QCLed RS/SS to a reception process almost at it is,and consequently, there is an advantage that an implementation/operationof an efficient receiver is available.

The QCL assumption in the AS aspect between two antenna ports means thatthe AS of a specific port may be derived/estimated/applied from the ASestimated from other port which is QCLed with the corresponding port.

The AS may be distinguished into Azimuth AS and Zenith AS, and in thiscase, the AS may be separately defined or defined together for eachspecific dimension. And/or, the AS may be distinguished into departureAS and arrival AS, and may be defined separately or together with foreach distinguished AS.

In the AS aspect, between antenna ports in which QCL isguaranteed/assumed, the QCL assumption for a reception beamwidth/sweeping degree (and/or a reception beam direction) is available.For example, a UE may mean that a reception of a transmission signal isavailable by configuring a reception beam width/sweeping degree (and/ora reception beam direction) from other antenna port(s) identically orsimilarly (in relation to it) with the AS estimated from specificantenna port(s). When the UE operates as such, a reception performanceis guaranteed higher than a specific level.

In summarizing the contents described above in relation to the AA andthe AS, the AA may be interpreted as a parameter in relation to average(the most) valid/dominant beam/spatial direction/angle, and the AS maybe interpreted as a parameter in relation to beam/space/anglespectrum/range for degree of spreading of beam direction by a reflectordistribution (based/centered on AA).

The AA and AS are parameters used in QCL assumption for a receptionbeam/space/angle management function. Therefore, the AA and AS may becollectively called a reception beam parameter, a reception beam relatedparameter, a reception angle parameter, a reception angle relatedparameter, a spatial QCL parameter, a spatial parameter, or a spatial Rxparameter. Hereinafter, for convenience of description, the AA and ASwill be collectively called the ‘reception beam related parameter’.

As reception beam related parameters, Angle of Arrival (AoA), DominantAoA, average AoA, Power Angular Spectrum (PAS) of AoA, average Angle ofDeparture (AoD), PAS ofAoD, transmit/receive channel correlation,transmit/receive beamforming, spatial channel correlation, and the likemay also be defined, which have the same/similar property as the AAand/or the AS described above.

QCL assumption between two antenna ports in terms of a power angle(-of-arrival) profile (PAP) means that PAP of a specific port may bederived/estimated/applied from PAP estimated from another port QCL withthe corresponding port (that is, a characteristic that the PAPs of twoports are the same as or similar to each other may bederived/estimated/applied). The PAP as a PAP for azimuth and/or zenithangle-domain may be defined separately or defined together for eachspecific dimension. In addition/alternatively, the PAP may be definedseparately or together in terms of a departure and/or an arrival.

The QCL guarantee/assumption in terms of the PAP may mean, for example,that a received beam width/sweeping degree (and/or received beamdirection) when receiving a transmission signal from another antennaport(s) based on the PAP estimated from a specific antenna port(s) isset to be the same as or similar to a corresponding specific antennaport(s) (or associated therewith) to receive the transmission signal.Furthermore, the QCL guarantee/assumption in terms of the PAP may meanthat the reception performance in this way is guaranteed at a specificlevel or higher.

In this specification, a new concept called “partial QCL (or may also bereferred to as a similar/modified name such as sub-QCL, fractional QCL,or quasi-sub-location (QSL))” is introduced in association with the QCLparameter.

A relationship such as “partial QCL (or may also be referred to as asimilar/modified name such as sub-QCL, fractional QCL, orquasi-sub-location (QSL))” may be established/configured/indicatedbetween specific antenna ports with respect to the at least one QCLparameter. For example, it may be assumed/configured/indicated that the“partial QCL” is established between a signal (and/or a resultingexperienced/observed (wireless) channel) transmitted from specificantenna port group A (e.g., the number of antenna port groups A may beone or more) and a signal (and/or a resulting experienced/observed(wireless) channel) transmitted from specific antenna port group B(e.g., the number of antenna port groups B may be one or more). In thiscase, it may be assumed/applied/utilized that QCLparameter(s)/property(s) for antenna port group A is a “sub-set (arelationship included in the same or higher set)” of QCLparameter(s)/property(s) estimated from antenna port group B. This maymean that performance is guaranteed at a predetermined level or higherwhen an association operation is applied based on theassumption/application/utilization.

The “partial QCL” has significance in various environments. In arepresentative example, a case may be considered in which a plurality ofphysical antennas form a single antenna network (SFN) to form logicalantenna port group A and logical antenna group B is mapped to individualphysical antennas. That is, in a representative example, a case may beconsidered in which a plurality of physical antennas (in particular,when LSPs are different for each physical antenna) is mapped to antennaports of logical antenna port group A and signals of correspondingantenna ports are transmitted through the plurality of antennas, butantenna ports of logical antenna port group B are mapped to any one ofthe plurality of physical antennas to which logical antenna port group Ais mapped to transmit signals of corresponding ports through the oneantenna. In the embodiment, a receiving end may derive the LSP of achannel to be experienced/transmitted by the signal transmitted throughlogical antenna port group B from the SLP of the channel acquired fromthe signal transmitted through logical antenna port group A (i.e.,partial QCL relationship/assumption is established).

For example, when logical antenna port group B has the partial QCLrelationship with respect to logical antenna port group A in a multipathfading panel environment, a relationship may be established/assumed inwhich channel delay values for/affecting the signal transmitted throughlogical antenna port group B are some of channel delay valuesfor/affecting the signal transmitted through logical antenna port groupA. In addition/alternatively, for example, when logical antenna portgroup B has the partial QCL relationship with respect to logical antennaport group A in the multipath fading panel environment, a relationshipmay be established/assumed in which channel Doppler values for/affectingthe signal transmitted through logical antenna port group B are some ofchannel Doppler values for/affecting the signal transmitted throughlogical antenna port group A. The receiving end may configure aparameter/LSP for a channel estimator of the signal received throughantenna port group B by using/based on the LSP acquired from the signalof logical antenna port group A by using such relationships. Inaddition/alternatively, for example, when logical antenna port group Bhas the partial QCL relationship with respect to logical antenna portgroup A in the multipath fading panel environment, a relationship may beestablished/assumed in which a reception beam direction (or angle/range)for receiving the signal transmitted through logical antenna port groupB belongs to/is included in a reception beam direction (or angle/range)for receiving the signal transmitted through logical antenna port groupA. The receiving end may search the reception beam direction (orangle/range) for receiving the signal transmitted through logicalantenna port group B among the reception beam directions (orangles/ranges) for receiving the signal transmitted through logicalantenna port group A by using such relationships. Therefore, thereceiving end may improve a search speed of the reception beam directionand/or reduce complexity of reception processing.

2. Inter/Intra-RS/SS QCL Relation

(In the NR environment,) At least one of the QCL parameters/propertiesdescribed above may be supported to be used in a UE operation by beingdefined/configured between specific RS/SS (e.g., between RS/SS ofdifferent types with each other among the RS/SS described below orbetween RS/SS of the same types).

-   -   PSS and/or SSS (this may be commonly called ‘synchronization        sequence/signal (SS) block’.)    -   BRS    -   BRRS    -   CSI-RS    -   PCRS (Phase noise Compensation Reference Signal)    -   DMRS

3. BRRS (Beam Refinement Reference Signal) QCL

In a beam refinement operation based on the BRRS, for channel estimationand the like for the BRRS itself, (when it is considered that a BRRStransmission in NR may have aperiodic property) it is required that RSdensity is supported such that the QCL assumption is available for aspecific QCL parameter/property (e.g., {Doppler spread and/or Dopplershift}) from much higher BRS, and so on.

As such, the RS/SS QCLed with the BRRS may be provided together when theRRC of the corresponding BRRS is configured, and this may mean thatsemi-static QCL configuration for BRRS is supported. Otherwise, in orderto provide more dynamic QCL configuration, QCL configuration of L2-level(and/or L1-level) may be configured/provided through medium accesscontrol (MAC) control element (CE) (and/or DCI) and so on for each BRRS.For example, all types of QCL configuration information of L2-level(and/or L1-level) may be provided to a UE (in real time) with fullflexibility, or a plurality of candidate QCL configuration parametersets is configured through RRC configuration and a UE is instructedthrough L2-level (and/or L1-level) signaling about which one isselected/applied/used among the parameter sets.

As an example of hierarchical QCL configuration instruction/signaling, ascheme is also available that an eNB configures a plurality of candidateQCL configuration parameter sets through RRC configuration to a UE, andfilters 2{circumflex over ( )}M (M>=1) parameter sets through L2-levelsignaling such as MAC CE primarily, and it may be instructed on whichparameter set is selected/applied/used among the parameter sets that arefiltered primarily through L1-level signaling through a specific DCI ofN-bit field to a UE. In other words, QCL configuration may behierarchized (e.g., through total third times) (or through a pluralityof times) and instructed/provided to a UE, and may be instructed throughRRC configuration primarily, L2-level signaling (e.g., MAC CE, etc.)secondarily, and L1-level signaling (e.g., DCI, etc.) thirdly. As such,hierarchized QCL configuration instruction scheme may be applied to theQCL configuration of other RS/SS in the same/similar manner as well asthe QCL configuration of the BRRS.

As such, the signaling scheme of RS/SS (e.g., BRS and/or PSS/SSS)information QCLed (with BRRS) provided for the purpose of channelestimation/measurement of BRRS through dynamic indication of L1 (and/orL2)-level may be very efficient in a wireless communication system inwhich “aperiodic or on-demand” BRRS transmission is considered.

More particularly, a transmitter may set at least one BRRS (resource(s))to a receiver in advance, and a transmitter (or an eNB) may instructinformation for a receiver to receive each BRRS dynamically throughL2-level (e.g., MAC CE) and/or L1-level (e.g., DCI). Here, theinformation for receiving each BRRS may include QCLed RS/SS information(with BRRS), for example, information of specific BRS port(s) and/orspecific PSS/SSS. As a result, there is an advantage that a transmitter(or an eNB) is able to perform a proper (aperiodic/on-demand) BRRStransmission very flexibly by considering an instantaneous situationsuch as loading of a UE and traffic/channel condition, and the like byusing BRRS transport resources that are preconfigured to a UE.

In order to support the operations described above efficiently, specificID may be provided to each BRRS (or BRRS resource) and/or each BRRSport(s), and/or specific ID may be provided to each BRS (or BRSresource) and/or each BRS port(s). Such a specific ID may be indicatedto a UE through QCL signaling for providing QCL configuration to the UEdescribed above.

When an eNB indicates RS/SS (e.g., specific BRS port(s)) informationQCLed for a specific BRRS to a UE (dynamically), the eNB may restrictQCL parameter/property to which QCL assumption is applied to a part ofthe numerated QCL parameters/properties.

For example, a UE may be restricted such that QCL assumption isavailable only for {Doppler spread, and/or Doppler shift}parameter/property. This is caused by the reason such as the case thatthere is a limitation in obtaining frequency synchronization only withthe BRRS safely. Particularly, the QCL assumption between BRRS and aspecific BRS may be support by an implementation scheme in the case thatBRRS and BRS are generated from the same oscillator.

And/or, a UE may be restricted that QCL assumption is (also) availablefor {Delay spread, and/or Average delay} parameter/property. Forexample, an eNB may configure/support the LSP of BRS QCLed with BRRS toa UE in the case that the LSP is guaranteed when it may be inferredbetween BRRS and BRS (transmitted from the same panel antenna, etc.),and accordingly, an efficient receiver implementation may be supported.

And/or, a UE may be restricted that QCL assumption is (also) availablefor {Average angle and/or Angular spread} parameter/property. Areception (analog) beam coefficients generation for receiving BRRS maybe applied by inferring from a beam coefficient generation which isapplied when receiving BRS, and accordingly, there is an advantage thatan efficient receiver implementation may be supported. Otherwise,considering that the AA of BRRS may be deviated with an angle differentfrom the AA of BRS with a specific level or higher, it may be set to aUE such that only “AS” is reflected (i.e., QCL assumption)(additionally).

4. CSI-RS QCL

In CSI-RS based CSI measurement and reporting operation, when a channelfor CSI-RS itself is measured, (considering that CSI-RS transmission mayhave aperiodic property in NR) it is required to support the QCLassumption for specific QCL parameter/property (e.g., Doppler spread andDoppler shift) from BRS or BRRS of which RS density is greater. Theinformation of RS/SS which is QCLed (with CSI-RS) may be provided whenRRC of the corresponding CSI-RS is configured together, and this may beinterpreted that semi-static QCL configuration for CSI-RS is supported.

Alternatively, in order to provide more dynamic QCL configuration, theQCL configuration of L2-level (and/or L1-level) through MAC (mediumaccess control) CE (control element)(and/or DCI) may beconfigured/provided for each CSI-RS (resource). For example, all typesof QCL configuration information of L2-level (and/or L1-level) may beprovided to a UE (in real time) with full flexibility, or a plurality ofcandidate QCL configuration parameter sets is configured through RRCconfiguration and a UE is instructed through L2-level (and/or L1-level)signaling about which one is selected/applied/used among the parametersets.

As an example of hierarchical QCL configuration instruction/signaling, ascheme is also available that an eNB configures a plurality of candidateQCL configuration parameter sets through RRC configuration to a UE, andfilters 2{circumflex over ( )}M (M>=1) parameter sets through L2-levelsignaling such as MAC CE primarily, and it may be instructed on whichparameter set is selected/applied/used among the parameter sets that arefiltered primarily through L1-level signaling through a specific DCI ofN-bit field to a UE. In other words, QCL configuration may behierarchical (e.g., through total third times) (or through a pluralityof times) and instructed/provided to a UE, and may be instructed throughRRC configuration primarily, L2-level signaling (e.g., MAC CE, etc.)secondarily, and L1-level signaling (e.g., DCI, etc.) thirdly. As such,hierarchical QCL configuration instruction scheme may be applied to theQCL configuration of other RS/SS in the same/similar manner as well asthe QCL configuration of the CSI-RS.

As such, the signaling scheme of RS/SS (e.g., BRS and/or PSS/SSS)information QCLed (with CSI-RS) provided for the purpose of channelestimation/measurement of BRRS through dynamic indication of L1 (and/orL2)-level may be very efficient in a wireless communication system inwhich “aperiodic or on-demand” CSI-RS transmission is considered.

More specifically, a transmitter may set at least one CSI-RS(resource(s)) to a receiver in advance. Instead of configuring all typesof configuration information (e.g., port number/(# of ports), scramblingID, time/frequency RE pattern, port subset (actually allocated port),QCLed (with CSI-RS) RS/SS information, and/or subframe period/offset)for CSI-RS measurement for each CSI-RS ID (or CSI-RS resourceconfiguration) semi-statically, only a part of information (e.g., portnumber/(# of ports), scrambling ID, and/or time/frequency RE pattern)among these may be configured (e.g., through RRC) semi-statically. Inthis case, a transmitter may indicate the remaining information elementsexcept the information element semi-statically configured throughL2-level (e.g., MAC CE) and/or L1-level (e.g., DCI). The remaininginformation elements may include QCLed (with CSI-RS) RS/SS information,for example, information of specific BRS/BRRS port(s) and/or specificPSS/SSS and the like. Here, semi-static configuration may mean that aspecific set among preconfigured candidate parameter sets is dynamicallyselected.

As a result, there in an advantage that a transmitter (or an eNB) isable to perform a proper (aperiodic/on-demand) CSI-RS transmission veryflexibly by considering an instantaneous situation such as loading of aUE and traffic/channel condition, and the like by using CSI-RS transportresources that are preconfigured to a UE.

In this embodiment, at least one CSI-RS (resource(s)) configured to a UEin semi-static manner may be interpreted as at least one “CSI-RScontainer(s) each with corresponding ID”. As such, transmission of each“CSI-RS container” on which aperiodic/“on-demand” CSI-RS is carried hasan advantage that efficiency of using CSI-RS transport resource ismaximized such that an eNB indicates optimal beamforming and QCLed RS/SSdynamically associated with the corresponding CSI-RS on everytransmission time.

The QCL assumption different from RS/SS may be configured/indicatedindependently for each CSI-RS resource to at least one CSI-RS resourceset to a receiver (or UE). For example, assuming that CSI-RS #1 and #2are set to a UE, it may be configured/indicated that CSI-RS #1 isQCL-assumed with specific BRS, and CSI-RS #2 is QCL-assumed withspecific BRRS. At this time, CSI-RS #1 may correspond to non-precodedCSI-RS, and/or CSI-RS for CSI-RS measurement initial step (e.g., CSI-RS#1 for hybrid CSI reporting based on CSI-RS #1 and #2), and in thiscase, it may be configured/indicated that CSI-RS #1 is QCLed withspecific BRS. On the contrary, CSI-RS #2 may correspond to CSI-RS #2configured for the purpose of link adaptation for improving transmissionefficiency by an eNB in a state that beamformed CSI-RS, and/or a UEaccess a specific BRS using serving-beam and progress beam refinementsufficiently through (subsequent) BRRS, and in this case, CSI-RS #2 maybe QCL configured/indicated with BRRS, not BRS.

And/or, in the case that a plurality of CSI-RS resources is configuredto a receiver (or a UE), QCL assumption may be configured/indicatedbetween a plurality of CSI-RS resources (for at least reception beamrelated parameters). For example, in the case that CSI-RS #1 and #2 areset to a UE, the UE may assume the QCL relation between antenna ports ofCSI-RS #1 and #2 (at least reception beam related parameters).

And/or, a receiver (or a UE) may be configured/indicated with QCLassumption between antenna ports in a single CSI-RS resource. Forexample, in the case that CSI-RS #1 is set to a UE, the UE may assumethe QCL relation between antenna ports corresponding to CSI-RS #1.

In order to support such various operations smoothly, QCL assumptionwith either one of BRS or BRRS may be selectively configured/indicatedto a CSI-RS. However, the present invention is not limited thereto, butaccording to an embodiment, QCL assumption for both of BRS and BRRS maybe configured/indicated to a CSI-RS, and a method of maximizing QCL RSdensity may also be supported together.

When an eNB indicates RS/SS (e.g., specific BRS port(s)) informationQCLed for a specific CSI-RS to a UE (dynamically), the eNB may restrictQCL parameter/property to which QCL assumption is applied to a part ofthe numerated QCL parameters/properties.

For example, a UE may be restricted such that QCL assumption isavailable only for {Doppler spread, and/or Doppler shift}parameter/property. This is caused by the reason such as the case thatthere is a limitation in obtaining frequency synchronization only withthe CSI-RS safely.

And/or, a UE may be restricted that QCL assumption is (also) availablefor {Average angle and/or Angular spread} parameter/property. This isbecause it is beneficial to reflect more stable beam with to CSI-RSreception process. Furthermore, when a beam width of CSI-RS is narrow,it may be set to a UE such that only “AS” is reflected (i.e., QCLassumption) (additionally).

And/or, a UE may be restricted that QCL assumption is (also) availablefor {Delay spread, and/or Average delay} parameter/property. This isbecause it is beneficial to reflect the QCL parameter such as BRStransmitted with wider band than CSI-RS transmission bandwidth to theCSI-RS reception process, considering the case that CSI-RS istransmitted with CSI-RS transmission bandwidth which is limited to apart of band.

5. DMRS QCL

When a UE is trying to receive DMRS-based PDSCH/EPDCCH, and the like,the channel estimation for DMRS is required, QCL assumption/signalingwith a specific CSI-RS, BRRS, and/or BRS may be supported for such DMRS.

For example, in the environment that it is determined that CSI-RSdensity is sufficient (by an eNB), it may be configured/indicated thatonly QCL between DMRS and specific CSI-RS resource(s) is applied.Alternatively, when it is considered that CSI-RS transmission hasaperiodic property and CSI-RS density is insufficient like NRenvironment, DMRS may be supported with QCL of other RS in which RSdensity is stably guaranteed in comparison with CSI-RS. In this case,DMRS may be QCLed with specific BRS, BRRS and/or PCRS, and direct QCLsignaling indicating such QCL configuration may be supported in a UE. Atthis time, the direct QCL signaling may be indicated to a UE even forspecific CSI-RS resource(s), PSS and/or SSS together/additionally aswell as the RS.

When the specific QCL configuration/indication between inter-RS/SS isprovided as described above, an inter-RS/SS QCL relationship may bedefined/configured in the format in which QCL application is availablebetween independent/separated/different RS and/or SS forspecific/individual QCL parameter. That is, when a UE assumes/appliesQCL, the UE may distinguish/change the applied QCL parameter accordingto RS/SS types that are QCLed with DMRS.

As an example, in the case that DMRS is QCLed with specific CSI-RSresource(s), a UE may be configured/indicated so as to assume/apply QCLlimitedly only for {Delay spread, Average delay, Average angle, Angularspread, and/or Average gain} parameter/property. In addition, in thecase that DMRS is QCLed with specific BRS, BRRS, PCRS, and/or PSS/SSS, aUE may be configured/indicated so as to assume/apply QCL limitedly onlyfor {Doppler spread, and/or Doppler shift}. This is because there is alimitation in estimating/applying {Doppler spread, and/or Doppler shift}parameter/property based on CSI-RS only.

As another example, in the case that DMRS is QCLed with specific BRS(s),BRRS(s), PCRS, and/or CSI-RS resource(s), a UE may beconfigured/indicated so as to assume/apply QCL limitedly only for {Delayspread, Average delay, Average angle, Angular spread, and/or Averagegain} parameter/property. In addition, in the case that DMRS is QCLedwith specific PSS and/or SSS, a UE may be configured/indicated so as toassume/apply QCL limitedly only for {Doppler spread, and/or Dopplershift}. This embodiment is applicable to the case that it guaranteesmore stable performance to estimate/apply {Doppler spread, and/orDoppler shift} parameter/property from PSS/SSS.

As another example, in the case that DMRS is QCLed with specific BRS(s),BRRS(s), PCRS, and/or CSI-RS resource(s), a UE may beconfigured/indicated so as to assume/apply QCL limitedly only for {Delayspread, Average delay, Average angle, Angular spread, and/or Averagegain} parameter/property. In addition, in the case that DMRS is QCLedwith specific BRS(s), BRRS(s), PCRS, and/or PSS/SSS, a UE may beconfigured/indicated so as to assume/apply QCL limitedly only for{Doppler spread, and/or Doppler shift} parameter/property. According tothis embodiment, in the case of specific BRS(s) and/or BRRS(s), QCLassumption is applicable for all (or most of) QCL parameters/properties,and simultaneously, in the case of specific CSI-RS resource(s), QCLassumption is applicable only for a part of limited QCLparameters/properties (e.g., except {Doppler spread, and/or Dopplershift}). As such, an eNB may differently configure/indicate applicablerange of QCL parameter/property for each RS/SS, and a part of multipleRSs/SSs are configured/indicated to be QCL-assumed with the same QCLparameter/property, and accordingly available number of RS samples maybe more increased. In this case, the most direct QCL application may beimplemented in the form that a priority is provided to a specific RS(e.g., CSI-RS), but QCL application from other RS (e.g., BRS, BRRS,and/or PCRS) may be considered together through weighted average, andthe like.

When assuming/signaling DMRS QCL (for the purpose of supportingnon-coherent joint transmission, etc.), different QCLconfiguration/indication may be applied to each specific DMRS port(s).For example, in the case that a UE is indicated with DMRS ports 7 to 10(through DL scheduling grant), the UE may be indicated such that the UEis available to be QCL-assumed with specific {BRS(s), BRRS(s), PCRS,and/or CSI-RS} for DMRS ports 7 and 8 among these, and available to beQCL-assumed with specific {BRS(s), BRRS(s), PCRS, and/or CSI-RS} forDMRS ports 9 and 10. This may be applied to the embodiment that DMRSports {7 and 8} and {9 and 10} may be transmitted from differentTransmission Reception Points (TRPs), or transmitted from differentantenna panels even in the same TRP, as a matter of fact. Through this,(non-coherent) joint transmission of various forms may be efficientlysupported.

The case may be assumed that specific DMRS is QCLed with specificCSI-RS, the corresponding CSI-RS is QCLed with specific BRS, and both ofthe DMRS QCL and the CSI-RS QCL are dynamically indicated by (separate)L1-level signaling (e.g., signaling by DCI). In this case, a timelineissue for the timing when the DMRS is QCL-assumed with the transmittedCSI-RS may occur. In other words, a timeline issue may occur that QCLwith the CSI-RS transmitted on a certain time is applied to DMRSreception/measurement.

In order to solve it, in the case that a signaling that specific DMRS(port(s)) is QCLed with specific CSI-RS ID #k is received in #n SF:

-   -   A UE may apply QCL assumption based on measurement samples of        CSI-RS ID #k received in a single SF timing (it may be limited        that this embodiment may be applied only to the case that        measurement restriction (MR) is set to be ON only for the        corresponding CSI-RS ID #k), of the corresponding CSI-RS ID #k        the most recently (successfully) received among the #n SF timing        or the previous SF timings, or    -   A UE may apply QCL assumption through combining/averaging with        measurement samples of CSI-RS ID #k of provided QCLed RS/SS        (e.g., BRS(s) and/or BRRS(s)) more prior timing (on which the        same information was provided by QCL signaling), as well as        measurement samples of CSI-RS ID #k received in a single SF        timing, of the corresponding CSI-RS ID #k the most recently        (successfully) received among the #n SF timing or the previous        SF timings.

6. PCRS QCL

PCRS is an RS defined for the purpose of phase drift adjustment/phasetracking, and may be transmitted with DMRS. A DMRS per each DMRS portgroup in which a plurality of DMRS ports is included may be interlinkedwith a single PCRS (e.g., has QCL/GCL relationship). PCRS may also bereferred as Phase Tracking (PT)-RS. Alternatively, in the case that PCRSis GCLed with DMRS in GCL aspect described below, DMRS may also bereferred to as a Primary DMRS or a Secondary DMRS (or PT-RS), and PCRSmay also be referred to as a Secondary DMRS or a Primary PCRS (orPT-RS).

It may be defined/configured that the QCL operation configured/indicatedto apply in order to receive/measure DMRS transmitted/scheduled togethermay be applied to the QCL required for receiving/measuring PCRS withoutany change/in the same manner. In the present disclosure, such arelationship is referred to as “genuine co-location (GCL)” relationship.That is, GCL means the QCL relationship in which not only a large-scaleparameter may be inferred between QCLed antenna ports, but also the moreparameters (e.g., small-scale parameter, etc.) may be inferred. As ageneralization, a UE may interpret that ‘GCLed (or having GCLrelationship) ports are treated as the same port, and available to bespecific time bundling and/or frequency bundling is available’. That is,in other words, an assumption of the same precoding is available to a UEby treating the ports in the GCL relationship as the same port,actually.

For example, PCRS may be defined/configured/indicated so as to beGCL-assumed with DMRS, and in this case, a UE may treat/regard the PCRSport and the DMRS port as the same port, and assume that the sameprocoding is applied to two antenna ports.

Such GCL concept will be described in more detail below in relation totransmission beam coordination and QCL.

And/or, a scheme is also available that the QCL required toreceive/measure PCRS is divided from the QCL of DMRStransmitted/scheduled together, and separate/independent QCL signalingis provided. At this time, separately divided QCL signaling may beprovided separately for each RS through DCI. Alternatively, in order toprevent aggravating DCI overhead problem, QCL signaling for PCRS may beseparated so as to be provided in semi-static scheme relatively than QCLsignaling for DMRS. For example, QCL signaling for PCRS may be providedL2-level signaling through MAC CE, and so on, and/or RRC signaling, andthe like. For example, DMRS may be configured/indicated such that QCLassumption is available with specific CSI-RS (and/or BRS and/or BRRS),or PCRS may be configured/indicated such that QCL assumption isavailable with specific (serving) BRS (and/or BRRS).

In the present disclosure, (QCLed/GCLed) (specific) RS/SS may beimplicitly indicated to be RS/SS for serving-cell/TP/beam, specifically.That is, a UE may be defined/configured such that the (QCLed/GCLed)(specific) RS/SS is RS/SS for RS/SS for serving-cell/TP/beam, and applythe QCL assumption therefor.

7. QCL Type

In the case of QCL type in LTE-A standard, an eNB configures RRC withQCL type B for CoMP operation such that a UE may perform dynamic pointselection (DPS) operation, and an eNB configures RRC with QCL type A fornon-CoMP operation such that a UE applies QCL among all RSs in a servingcell with each other.

In NR environment, an operation of being served for a virtualcell/sector formed in a specific beam direction as well as cell/TP(e.g., by analog beamforming). When such a virtual cell/sector iscommonly called “beam” for the convenience of description, it isrequired that inter-beam CoMP operation such as Dynamic “beam” selectionis also available. A particular example for this will be described byreference to FIG. 10 below.

FIG. 10 illustrates an antenna panel model in which analog beamformingis applied for each panel to which the present invention may be applied.

As shown in FIG. 10, through the transmission antenna configurationhaving “multi-panel antenna” structure, it may be assumed the situationthat specific analog beamforming is applied to each panel, and eachforms “virtual cell/sector/beam”. In such a situation that a signaltransmitted from a transmitter is not dominant in a particular beamdirection (e.g., from a particular panel) for a specific receiver, andsignal qualities of two or more beam directions show a difference withina specific level, the performance improvement may be expected throughthe DBS described above.

Accordingly, in the present disclosure, it is proposed that specific QCLtype B′ in which a receiver may support such an operation isdefined/configured, and accordingly, the receiver may perform beam-basedCoMP operation like DBS smoothly. In addition, QCL type A′ may besupported as a mode in which QCL assumption may be applied between RSsthat correspond to serving cell/TP/beam.

In summarizing the proposed contents, QCL type switching may bedefined/configured in the following forms.

A UE to which transmission mode x for serving cell/TP/beam is configured(or configured for New RAT operation) may be configured with one of thefollowing QCL types below for serving cell/TP/beam by higher layerparameter, in order to decode PDSCH according to a transmission schemeassociated with antenna ports (e.g., ports 7-14) in relation to DMRS.

-   -   Type A′: For a UE, the antenna ports in relation to BRS (and/or        BRRS and/or PSS/SSS) of serving cell/TP/beam is QCLed with at        least one of the QCL parameters/properties described above.    -   Type B′: For a UE, the antenna ports XX-YY corresponding to        CSI-RS (and/or BRS/BRRS) configuration distinguished by higher        layer parameter and the antenna ports (e.g., 7-14) in relation        to DMRS associated with PDSCH are QCLed with at least one of the        QCL parameters/properties described above.

The scheme may be also applied that QCL type B′ among the configurableQCL types is replaced by QCL type C′ described below, it is limitedlydefined such that semi-static switching between QCL type A′ and QCL typeC′ only is available, or all of QCL types A′ to Cl′ are defined and asingle type is selectively configured by RRC signaling, and the like.

-   -   Type C′: For a UE, the antenna ports in relation to BRS/BRRS        (and/or PCRS) of a specific beam that corresponds to BRS/BRRS        configuration and the antenna ports (e.g., ports 7-14) in        relation to DMRS associated with PDSCH is QCLed with at least        one of the QCL parameters/properties described above.

However, it is apparent that such description in relation to QCL types Ato C may be modified/defined such that the QCL related proposal elementproposed in the present invention is reflected in various manners. Thatis, when QCL type is switching by setting A′ and B′ or QCL type C thatindicates direction QCL with specific BRS is supported(together/additionally) in addition to QCL type A′ and B′, in thedetailed description including the applicable QCL type/property, thetechnical element proposed in the present invention may bereflected/substituted and defined/modified/defined.

In the present disclosure, various RSs are referred to as BRS, BRRS,PCRS, and the like, for the convenience of description, but theapplication of the present invention is not limited thereto, but it isapparent that the present invention may also be applied to RS of otherterm having the same/similarform/function/purpose of the correspondingRS.

In addition, the control information configured/indicated in aUE/receiver may be forwarded by RRC, MAC CE, and/or DCI, and a form ofsignaling among signaling of such L1 and/or L2 level in which thecorresponding configuration/indication is provided may bedefined/configured differently/independently for each individual controlinformation.

Transmission Beam Coordination for NR and QCL

In the NR environment, single/multi point transmission may be supportedfor both of DL MIMO and UL MIMO. In addition, in the NR environment, ameasurement assumption for QCL assumption and antenna ports may beperformed. Based on this, hereinafter, intra/inter-TRP coordinationtransmission in which QCL is assumed between specific RSs will bedescribed below.

1. Intra-TRP Coordination Transmission

Various antenna panel arrangement structures have been considered in theNR environment/system. A first panel model may be distinguished as auniform 1D/2D rectangular panel array. Since a proper CSI-RSresource/port should be configured with a UE through such antenna array,an efficient closed-loop MIMO transmission may be applied based on theCSI measurement and feedback of a UE. CSI-RS port and antenna arraymapping are dependent upon eNB implementation and various mappingschemes may be existed, for example, the following schemes may beexited: (1) a CSI-RS resource per panel, (2) a plurality of CSI-RSresources per panel, and (3) CSI-RS resource mapped to a plurality ofpanel, is mapped.

FIG. 11 illustrates a scheme in which a single CSI-RS resource is mappedper panel according to an embodiment of the present invention.

The embodiment shown in FIG. 11 shows the simplest method of CSI-RSmapping that a CSI-RS resource is transmitted in a panel and CSI-RSports in CSI-RS resource may be QCL-guaranteed/assumed. That is,according to this embodiment, between (a part or all) CSI-RS ports in asingle CSI-RS resource, the QCL may be assumed/guaranteed for at least apart (e.g., parameter in relation to average gain, delay spread, Dopplerspread, Doppler shift, average delay and/or reception beam) among theQCL parameters/properties described above. Such QCLassumption/guaranteeing may be performed in the case that the sameoscillator (having related component) in order to generate a signal inCSI-RS ports (included in a single CSI-RS resource or mapped to a singlepanel).

This may be interpreted as a single (virtual) cell operation accordingto the conventional art, and the single virtual cell may be associatedwith a UE by measuring an RS port that corresponds to Radio resourcemanagement (for the convenience of description, hereinafter, referred toas ‘RRM-RS’). According to the RRM-RS and detailed RS design forpotentially aperiodic/sub band CSI-RS, in order to support a UEimplementation, a proper QCL assumption is required between CSI-RSresource and specific RRM-RS.

FIG. 12 illustrates a scheme in which a plurality of CSI-RS resources ismapped per panel according to an embodiment of the present invention.

The embodiment shown in FIG. 12 may be interpreted as multiplebeamformed CSI-RS based operation similar to Full Dimension (FD)-MIMOclass B having multiple Beamformed (BF) CSI-RS resources. Since such aplurality of CSI-RSs transmitted from a single panel is oriented todifferent beam directions, it cannot say that each CSI-RS and thecorresponding RRM-RS are in QCL always for all QCLproperties/parameters. Similar to the definition in LTE specification,in the QCL assumption between CSI-RS and RRM-RS for this case, forexample, only a part of properties/parameters such as Doppler shift andDoppler spread may be used, and this may be explicitly indicated. Sincesuch a difference is caused by different CSI-RS mapping scheme forantenna array, NR specification should support various implementationschemes of CSI-RS antenna port mapping of different purposes properly.

FIG. 13 illustrates a scheme in which CSI-RS resource shared by aplurality of panels is mapped according to an embodiment of the presentinvention.

The embodiment shown in FIG. 13 may be interpreted as the shared CSI-RSresource which is mapped to a plurality of panels so as to have morebeamforming gain in the CSI-RS transmitted by cooperative transmissionfrom a plurality of panel antennas. Such a scheme in which CSI-RS portis mapped to a plurality of panels may be particularly useful for thecase of intended to support SU-MIMO transmission for a specific UE inwhich traffic load is small. When it is assumed that a network obtainssufficient information of beamforming direction for a target UE, theCSI-RS may be used as a UE-specific beamformed CSI-RS dedicated to theUE. In order to properly support a use scenario, when QCL assumption isrequired, it is required to examine the QCL assumption between CSI-RSand RRM-RS and the way of definition or support of signaling for NRoperation.

In summarizing the contents described above, according to a CSI-RSresource mapping method for multi-panel Transmission Point (TP), variousintra-TRP coordination transmission scheme may be considered in NR. Inaddition, a proper QCL assumption between RS(s) for RRM and CSI-RS(s)set to a UE may be required to support the intra-TRP coordinationtransmission.

2. QCL Type and Signaling

In the case that QCL assumption between different antenna ports isrequired in NR in order to improve channel estimation performance, inthe embodiments shown in FIGS. 11 to 13, different QCL types and similarsemi-static configurations may be supported such as being defined in LTEspecification (UE of TM 10 is configured with QCL type A or B by RRCsignaling).

However, in the NR context, together with the CSI-RS transmission(vigorously discussed in Rel-14 eFD-MIMO) of aperiodic type which hasbeen considered, in order to use efficiently in a reception operation inUE side, it is preferable to research the QCL type which is configurablemore dynamically and the corresponding QCL assumption. In other words,each UE may be configured with specific CSI-RS resource(s) that has afew essential RRC parameters, but actual CSI-RS transmission may becontrolled by an eNB through L1-signaling. Here, the controllablecomponent may include actual transmission instance, time/frequency REpattern, number of ports, applied port numbering and/or scrambling seed.Such a dynamic CSI-RS allocation and transmission may require support ofmore flexible QCL signaling with other RS that includes RRM-RS in moredynamic scheme. That is, dynamic CSI-RS allocation and transmission forNR may require more flexible QCL signaling support for other RS thatincludes RRM-RS.

3. Other QCL parameter/property

In current LTE specification, five LSPs for QCL between antenna ports,that is, delay spread, Doppler spread, Doppler shift, average gain, andaverage delay are defined. Except such existing QCL parameters,especially when analog beamforming is applied in UE side, it may berequired to consider a property of a new type of arrival angle/beam forNR research.

During beam scanning/tracking procedure, a UE may select several TX-RXanalog beam pair by measuring and comparing a quality of specific DL RS(for the convenience of description, referred to as ‘RRM-RS’). An eNB(or may be referred to as gNB) may select one of UE-preferredtransmission (TX) beams in order to transmit beamformed CSI-RS or DMRSports. In this case, the UE should know which reception (RX) beamreceives these antenna ports among candidate RX beams such that the TXbeam ID corresponding to RRM-RS port is to be signaled to the UE. Inthis situation, it can be said that the RRM-RS port and the CSI-RS/DMRSport are QCLed in the aspect of dominant arrival angle according to theQCL definition as below.

-   -   In the case that the LSP of a channel through which a symbol of        an antenna port is transferred is able to be implied/inferred        from the channel through which a symbol of other antenna port is        transmitted, it can be said that two antenna ports are QCLed.

The Dominant arrival angle may determine an RX beam formationcoefficient. In addition, since an analog beam may not be dynamicallychanged on comparison with a digital beam, the Dominant arrival anglemay be regarded as LSP relatively. Without QCL assumption, a UE shouldsearch a plurality of RX beam candidates, and this is time andfrequency-consuming.

Accordingly, in the NR environment, a new type of QCL property needs tobe considered for arrival angle when analog beamforming is applied in UEside, the reception beam related parameter described above may bedefined as a new type of QCL parameter.

4. Transmission coordination between inter-RS QCL and TRP

In designing RRM-RS, in order to assist RRM-RS measurement, it should beconsidered whether a part (e.g., Doppler shift and average delay) of QCLparameters/properties obtained from synchronization signals isQCL-assumed for RRM-RS. When a UE tracks such RRM-RS(s) once, this maybe used for QCL linkage of the second level of RRM-RS for minuter beamrefinement which may be UE-specifically beamformed for the UE. Asdescribed above, it is required to be indicated that CSI-RS follows QCLlinkage for primary or secondary RRM-RS(s). When sub band CSI-RS is setto a UE, for example, it may be beneficial to follow QCL for otherCSI-RS which is transmitted in broadband.

In the current LTE specification, a UE to which TM10 having QCL type Bis configured may be scheduled to receive a PDSCH transmitted from anon-serving cell/TP as CoMP Dynamic point selection (DPS) operation. Atthis time, the DMRS for a PDSCH may be instructed to follow at least oneof CSI-RSs configured by PQI filed in a DCI and QCL. In other words, theDMRS fora PDSCH may be configured to have QCL relation with at least oneof CSI-RSs indicated by PQI field. In such a DPS operation, in the factthat an actual dynamic TRP selection is performed according to aconfigured CSI-RS resource (e.g., each CSI-RS resource configured foreach TRP) or a dynamic beam selection (DBS) is performed in a singleTRP, a similar operation to the DPS operation may be considered inNR-MIMO. This may be interpreted as intra-TRP CoMP in beam coordinationaspect.

In order to properly support these kinds of various transmissionstrategies in NR, the DMRS for PDSCH should also be explicitly indicatedto follow QCL to other RS, e.g., CSI-RS or RRM-RS, unless DMRS designfor NR study is done without requiring any other QCL supports and byguaranteeing sufficient RS density within the scheduled band.

Particularly, in order to support phase compensation at UE side owing tophase noise effect, the second level of DMRS (i.e., secondary DMRS) maybe transmitted to a scheduled PDSCH which is wanted to be distributedthroughout a time domain like several symbols of the same subcarrier.Since such secondary DMRS is an RS transmitted to support the phasecompensation at UE side, the secondary DMRS may be the conceptcorresponding to the PCRS (or PT-RS) described above. Accordingly, thesecondary DMRS may be referred to as the PCRS (or PT-RS) or substitutedby the PCRS (or PT-RS).

It may be assumed that the secondary DMRS may be QCLed with the primaryDMRS for all QCL parameters/properties, and the QCL in this case may beinterpreted to the GCL described above. Here, the GCL is available fortime/frequency bundling between antenna ports as described above, andindicates that these are the same port efficiently. As a result, a UEmay receive DMRS by assuming the same precoding between GCLed antennaports.

In summary, the first and second DMRSs are distributed/transmitted overa plurality of symbol regions (i.e., multiple time regions, e.g.,continuous time regions) in the same subcarrier region, where a GCLrelationship may be indicated/configured between the first and secondDMRSs. When the UE is indicated/configured with the GCL relationship ofthe first and second DMRSs, the UE can receive the DMRS assuming thesame precoding between the first and second DMRS ports.

The GCL relationship in the embodiment described above is interpretedwith DMRS (or data demodulation) aspect mainly, and may also beinterpreted/described PCRS (or phase compensation) mainly. That is, inthe embodiment described above, although the secondary DMRS (orPCRS/PT-RS) is used for the purpose/effect of receiving DMRS stably byincreasing DMRS density, on the contrary, the primary DMRS may be usedfor the purpose/effect of receiving DMRS stably by increasing PCRS (orPT-RS) density.

In describing the embodiment in the above-described aspect again, theprimary and secondary PCRSs (or PT-RSs) (corresponding to the primaryand secondary DMRSs) may be transmitted throughout/being distributed ina plurality of symbol domains (i.e., several time domains, e.g.,consecutive time domains) in the same subcarrier domain (i.e., the samefrequency domain), and in this case, the GCL relationship may beindicated/configured between the primary and secondary PCRSs (orPT-RSs). When a UE is configured with the GCL relationship between theprimary and secondary PCRSs (or PT-RSs), the UE may receive PCRS (orPT-RS) by assuming the same precoding in the between the primary andsecondary PCRSs (or PT-RSs) ports.

In generalizing the embodiment described above, consequently, the DMRSand the PCRS (or PT-RS) having the GCL relationship may be distributedin a time domain and transmitted to a UE in the same frequency domain,and the UE may receive the DMRS and the PCRS (or PT-RS) by assuming theGCL relationship between the DMRS and the PCRS (or PT-RS) and byassuming the same precoding. At this time, the DMRS and the PCRS (orPT-RS) which are GCLed may be named according to GCL purpose (e.g., datademodulation purpose or phase compensation purpose). In the case thatthe DMRS and the PCRS (or PT-RS) which are GCLed may be referred to asthe primary and secondary DMRSs in the case that these are in the datademodulation purpose, and may be referred to as the primary andsecondary PCRSs (or PT-RSs) in the phase compensation purpose. However,the DMRS and the PCRS (or PT-RS) which are GCLed are not limitedthereto, but may also be substituted by the RS (or RS name) having thesame purpose/function/effect.

In conclusion, to properly support various intra/inter-TRP coordinatedtransmissions, DMRS QCL to CSI-RS or RRM-RS may need to be dynamicallyindicated, unless DMRS design for NR is done without requiring any QCLsupports and by guaranteeing sufficient RS density.

It means that the GCL concept described above is available toconfigure/indicate specific “{frequency, time, space, and/orcode}-domain bundling/aggregation”,

-   -   In the case of frequency-domain bundling, a transmitter (e.g.,        eNB) may indicate bundling to a receiver (e.g., UE) with a        subcarrier level, an RB level, an RB group (e.g., RBG) level,        and/or a sub band level, and the like.

In the case of time-domain bundling, a transmitter (e.g., eNB) mayindicate bundling to a receiver (e.g., UE) with a symbol level, a slotlevel, a (mini-) subframe level, or a subframe group (e.g. TTI bundling)level, and the like.

-   -   In the case of space-domain bundling, a transmitter (e.g., eNB)        may indicate bundling to a receiver (e.g., UE) with a port/beam        level, and the like, and the ports/beams in this case may        correspond to corresponding specific RSs and/or channels (e.g.,        in the case that the same precoder should be used for nominal        ports/beams distinguished in a transmitter.).

In the case of code-domain bundling, a transmitter (e.g., eNB) mayindicate bundling to a receiver (e.g., UE) with specific other sequences(e.g., generated by different scrambling parameters) or between othercover codes (e.g., OCC).

As such, a receiver is configured/indicated with the fact that specific(available to apply {frequency, time, space, and/or code}-domainbundling) GCL assumption is available between RSs, SSs, and/or channels,the receiver may apply the GCL assumption between RSs, SSs, and/orchannels, and may improve a reception performance by {frequency, time,space, and/or code}-domain bundling. Such an operation makes it possibleto configure/indicate such GCL assumption (temporarily) in a specificcase for a receiver by an intension of a transmitter, although commonoperation is different between RSs, SSs, and/or channels, and has anadvantage that various transmission flexibilities are provided and areception performance is improved.

For example, as exemplified above, the intended operations may bedifferent between the PCRS and the DMRS (different antenna port numbermay be provided) basically (e.g., the PCRS is in the phase compensationpurpose, and the DMRS is in the data demodulation purpose), and in thecase that configuration/indication that the GCL assumption is availableis provided, the GCLed PCRS may be utilized in DMRS reception process(with the DMRS) for the data demodulation purpose, and accordingly, areception performance may be improved.

As another example, in addition to such an operation between specificRSs, according to the GCL relationship configured/indicated byconsidering the relationship of “PSS/SSS/ESS (Extended SynchronizationSignal) and/or BRS”, PSS may be utilized as a channel estimationreference signal of SSS, and accordingly, SSS reception performance maybe improved. Similarly, in the case that BRS is also configured suchthat the GCL assumption is available with specific PSS/SSS/ESS, it isavailable to improve a reception performance of the BRS through this.

In addition, the GCL assumption may be configured/indicated such that aUE may perform bundling by GCL assumption application with respect tospecific different {frequency, time, space, and/or code}-domain bundlingeven for the same RS, SS or channel.

For example, in the case that the GCL assumption is configured/indicatedfor specific time instances with respect to specific CSI-RS (resourceand/or port(s)), even in the case that actual each CSI-RS transmissionis (1-shot) dynamically indicated by a DCI, a UE may average/combine themeasurement samples between such 1-shot CSI-RS measurement throughoutthe GCLed (or GCL assumption is configured/indicated) time instances. Inthe aspect of a transmitter, with respect to the GCLed time instances,for example, this may mean that beamforming coefficients applied whenapplying each CSI-RS transmission should not be changed. Consequently,the precoder applied when transmitting each beamformed CSI-RS may betransmitted in receiver-transparent manner, but a transmitter mayguarantee that the CSI-RS in which same precoder is maintained/appliedis transmitted in the GCLed time instances. With this, there is aneffect that a receiver measures and combines the GCLed (aperiodic)CSI-RSs and secures adequate measurement samples, and through this,specific LSPs may be estimated. With the LSP estimated as such, the QCLconfiguration/indication described above is available with another RS(e.g., DMRS), and through this, the data demodulation performance basedon DMRS may be improved.

As described above, GCL indicator (e.g., GCL indication field defined inDCI) that configures/indicates GCL may be configured with 1-bit field,and the like, and may be implemented with a “toggling” form. That is,for example, in the case that a GCL indicator transmitted whileaperiodic CSI-RS transmission is triggered is ‘0’ and a GCL indicator ofCSI-RS transmission (of the same ID as the corresponding CSI-RS)transmitted/measured the most recently is also ‘O’ (i.e., a GCLindicator is not toggled), a UE may apply the GCL assumption betweenthese two CSI-RS transmission, and may performbundling/combining/averaging operation. In such a way, in the case thatthe UE also transmits a GCL indicator for a subsequent CSI-RS in a formof not toggled, the UE may perform bundling for the subsequent CSI-RScontinually. In the case that a GCL indicator for the subsequent CSI-RSis transmitted with being toggled, the UE may not perform bundling forthe corresponding CSI-RS any more.

As such, the operation that a UE determines whether to perform/applybundling according to a GCL indicator value (e.g., whether to toggle)indicated for the most recently transmitted CSI-RS may be limited to thescheme that it is determined whether to apply the GCL assumption bycomparing (by toggling) with the most recent instance in the set inwhich only the CSI-RS instances indicated by the same QCL as the QCLwith other RS (e.g., BRS and/or BRRS) of the corresponding CSI-RS (evenin the case of the same CSI-RS ID). This is because a CSI-RStransmission QCLed with other RS (e.g., BRS and/or BRRS) may be flexiblytransmitted aperiodically as described above, even in the case of thetransmission by the same CSI-RS ID. Consequently, as such, a UE may belimited to the scheme that the QCL assumption is applied within theCSI-RS transmission instances that follow the same ‘CSI-RS to other RS(e.g., BRS and/or BRRS) QCL’.

Such a limited operation may be signaling-indicated to a UE in variousmanner such as bundling is applied by collecting the CSI-RS transmissioninstances of which CSI process ID indicated by the corresponding DCIfield are the same in the case that DCI field is configured in thefollowing forms, in addition to the method that bundling is applied bycolleting the CSI-RS transmission instances of which ‘CSI-RS to other RS(e.g., BRS and/or BRRS) QCL’ are the same. In addition, as representedin the following Table, the way of determining the limited set may beimplemented with various embodiments by the DCI field which is applied.

TABLE 4 5.3.3.1.3 Format B1 DCI format B1 is used in scheduling ofxPDSCH The information below is transmitted through DCI format B1 insubframe n . . . CSI/BSI/BRI request - 3bits If an indicated value is‘000’, CSI/BSI/BRI is not requested. If an indicated value is ‘001’,this DCI format triggers BSI reporting. If an indicated value is ‘010’,this DCI format allocates BRRS, and triggers corresponding BRI report.If an indicated value is ‘011’, this DCI format allocates BRRS, but doesnot trigger BRI report. If an indicated value is ‘100’, this DCI formatallocates CSI-RS, and triggers corresponding BRI report. ‘101’, ‘110’and ‘111’ are reserved. . . . If this format allocates either one ofCSI-RS or BRRS transmission, process indicator - 2bits 00: {Process #0},01 : {Process #1}, 10 : {Process #2}, 11 : {Process #3} . . .

Only part of examples are described in the present disclosure, but theGCL relation operation may be applied by substituting QCL by GCL (andthe related definition/attribute) even for all QCL related proposedoperations described in the present invention (since the GCL concept isapplying more fortified properties than the QCL).

SS Related QCL Definition/Concept

PSS, SSS, and/or PBCH may be transmitted within ‘SS block (SSB)’. Inexcluding another signal, another signal is not excluded in the SSblock. One or a plurality of SS block(s) may constitute an ‘SS burst’.One or a plurality of SS burst(s) may constitute an ‘SS burst set’. Thenumber of SS bursts in the SS burst set may be finite. Hereinafter, howto configure the SS blocks and the SS bursts will be described in moredetail.

In the NR, PSS, SSS, and/or PBCH may be defined for delivering initialaccess related information (e.g., symbol timing, cell-ID, requiredsystem information, and/or information for initial UL transmission,etc.). Furthermore, further discussion is underway in the NR to defineother new signals/channels for required system information delivery orcell/TRP/beam measurements. Thus, several signals/channels (e.g., NR-SS,NR-PBCH, control channel, measurement RS, etc.) for initial access maybe defined in the NR. In this case, the signals/channelsconfigured/composed in the SS block may be changed according to atransmission occasion if a periodicity of each signal/channel for theinitial access is different. That is, another set of initial accessrelated signals/channels may be configured/composed within the SS block.In this regard, various types of SS blocks may be defined as followsaccording to a kind of configured/composed signal/channel in the SSblock:

-   -   Type 1: NR-SS (PSS and SSS)    -   Type 2: NR-SS and NR-PBCH    -   Type 3: NR-SS and MRS    -   Type 4: NR-SS and control channel

The signal/channel may be multiplexed in the SS block. According to thetype of signal/channel composed in the SS block, duration of the SSblock may be changed. For example, in the case of TDM, theabove-described Type 1 (NR-SS only) and Type 2 (multiplexing NR-SS andNR-PRBCH) may have different SS block duration. However, regardless ofthe type of signal/channel composed in the SS block, it may be desirableto maintain the duration of the SS block. Furthermore, considering thatthe duration of the ‘SS burst’ is determined by the duration of the ‘SSblock’, fixed duration of the SS burst should also be considered.

FIG. 14 is a diagram illustrating duration of an SS block and an SSburst which may be applied to the present invention.

Referring to FIG. 14, considering that the duration of the ‘SS burst’ isdetermined by the duration of the ‘SS block’, the fixed duration of theSS burst may be preferred regardless of the type of composedsignal/channel in the SS block. Therefore, it may be assumed that eachtype of SS block has the same duration regardless of all kinds ofcomposed signals/channels in the SS block.

DL control signaling may be located in a first OFDM symbol(s) of a slotand/or minislot. Further, a UL control channel may be located in thevicinity of UL symbol(s) last transmitted in the slot. Therefore, it canbe seen that a DL control channel and a DMRS are located in first N OFDMsymbols and the UL control channel is located in last N OFDM symbols inthe slot. In order to avoid conflict between the ‘SS block’ and theDL/UL control channel, the SS block may be located in the middle of theslot. Consecutive (or contiguous) SS blocks within the slot may be usedto constitute the ‘SS burst’. Further, when the plurality of SS blocksfor the SS burst is spread across a plurality of slots, inconsecutive(or non-contiguous) ‘SS blocks’ may be needed to constitute the ‘SSburst’.

FIG. 15 is a diagram illustrating an SS burst configuration for a TDDcase which may be applied to the present invention.

As described above, both the consecutive and inconsecutive ‘SS blocks'need to be used to constitute the ‘SS burst’. Therefore, both theconsecutive ‘SS blocks' and the inconsecutive ‘SS blocks' may be used toconstitute the ‘SS burst’. In other words, the SS blocks constitutingthe SS burst may be located consecutively and/or located inconsecutively(in a time domain).

To sum up the above contents with respect to FIGS. 14 and 15, thefollowing conclusion/proposal may be derived.

Considering that the duration of the ‘SS burst’ is determined by theduration of the ‘SS block’, the fixed duration of the SS burst may bepreferred regardless of the type of composed signal/channel in the SSblock. Therefore, it may be assumed that each type of SS block has thesame duration regardless of the type of composed signals/channels in theSS block.

-   -   Both the consecutive and inconsecutive ‘SS blocks' may be        required to constitute the ‘SS burst’. Therefore, both the        consecutive and inconsecutive ‘SS blocks' may be used to        constitute the ‘SS burst’.

Hereinafter, various techniques will be proposed, which a specific QCLparameter/characteristic acquired through reception of a synchronizationprocedure related signal (area/block) of the SS block or the like isapplied to another RS (group) assumed/configured/indicated to establishQCL and/or partial QCL with the corresponding signal (area/block) (e.g.,for beam management) to reduce reception complexity of the another RS(group) and/or enhance detection performance. Prior to varioustechniques, contents based on the proposed techniques will bepreferentially described.

The following signal combinations may be considered for inter-cell RRMmeasurements for CONNECTED and IDLE.

1. Option 1: Same RS

-   -   Option 1-1: NR-SSS and/or NR-PSS    -   Option 1-2: Mobility RS (MRS)-1 (Multi-port multi-beam reference        signal multiplexed in SS block)    -   Option 1-3: Mobility RS (MRS)-2 (Multi-port multi-beam reference        signal not multiplexed in SS block)    -   Option 1-4: Mobility RS (MRS)-3 (Single/multi-port single-beam        reference signal)    -   Option 1-5: NR-SSS and DM-RS for PBCH, if DM-RS for PBCH is        supported

2. Option 2: Not same RS

-   -   Option 2-1: NR-SSS in an IDLE state; MRS-{1,2} in a CONNECTED        state    -   Option 2-2: NR-SSS in the IDLE state; NR-SSS and MRS-{1,2} in        the CONNECTED state    -   Option 2-3: NR-PSS and/or NR-SSS in the IDLE state; NR-PSS        and/or NR-SSS in the CONNECTED state, and CSI-RS    -   Option 2-4: In the CONNECTED state, the RS and MRS-{1,2,3} in        the IDLE state

At least the following aspects should be considered and results andanalysis should be provided.

-   -   Cell coverage of CONNECTED and IDLE    -   Overhead (e.g., the number of resource elements, a bandwidth        (BW) used for RS mapping, and resource usage over time) of an RS        resource    -   Accuracy of an RS measurement quantity

The following effect may be considered in a multi-beam case due to IDLEmode RS option selection:

-   -   Performance in DL/UL signal reception after RACH before RRC        connection in association with associated beams acquired during        a random access channel (RACH) procedure

The CSI-RS supports DL Tx beam sweeping and UE Rx beam sweeping. TheCSI-RS may be used in mode P1, P2, and/or P3.

The NR CSI-RS supports the following mapping structure.

-   -   N_P CSI-RS port(s) may be mapped for each (sub) time unit.        Throughout the entire (sub) time unit, the same CSI-RS antenna        ports may be mapped. Here, “time unit” means n (>=1) OFDM        symbols in configured/reference numerology.    -   Each time unit may be divided into sub-time units. In this case,        as a division method, a division method which is the same as        division of TDM, IFDMA, and OFDM symbol-level having an OFDM        symbol length (i.e., a larger subcarrier interval) which is        equal to or smaller than a standard/preset/reference OFDM symbol        length (subcarrier interval) may be used, but another division        method is not also excluded.    -   The/aforementioned mapping structure may be used for supporting        multi-panels/TX chains.

CSI-RS mapping options for Tx and Rx beam sweeping may be describedbelow:

-   -   Option 1: Tx beams may be the same as each other over the sub        time unit within each time unit, but may be different over the        time unit.    -   Option 2: Tx beams may be different for each sub time unit        within each time unit, but may be the same as each other over        the time unit.    -   Option 3 (Combination of Option 1 and Option 2): The Tx beam(s)        are the same over the sub time unit within onetime unit. The Tx        beam(s) may be different over the sub time unit within different        time units. Only Tx sweeping or Rx sweeping may be available.

Hereinafter, for convenience of description, a CSI-RS (whose RS name maybe changed) that may be configured as a (sub) time unit type for aspecific beam management purpose or the like will be referred to as aType 2 CSI-RS and a CSI-RS which may be configured as another type(e.g., a CSI-RS type of 3GPP LTE/LTE-A) will be referred to as a Type 1CSI-RS, and each type of CSI-RS will be described below with referenceto FIGS. 16A and 16B.

FIGS. 16A and 16B illustrates a type 1 CSI-RS and a type 2 CSI-RS whichmay be applied to the present invention. In particular, FIG. 16A andFIG. 16B illustrate the Type 1 CSI-RS and the Type 2 CSI-RS,respectively.

Referring to FIG. 16A, in the case of the existing CSI-RS configurationscheme (i.e., type 1 CSI-RS configuration scheme), the CSI-RS portnumber and/or the sequence generation/scrambling parameter may be setand a specific/period/offset may be set (may be omitted in the case ofaperiodic CSI-RS, etc.). Further, the case of the existing CSI-RSconfiguration scheme (i.e., type 1 CSI-RS configuration scheme) followsa structure in which a location (e.g., CSI-RS RE location/pattern) of afrequency/time resource in which the CSI-RS is transmitted at eachCSI-RS transmission instance is set in advance (RRC signaling). Forconvenience, this is referred to as Type 1 CSI-RS as described above.

Unlike this, a specific CSI-RS resource configuration may be furthersubdivided by a “(sub) time unit” related configuration and a detailedoperation option for an operation of a UE, etc. may be furtherconfigured with respect to the corresponding (sub) time unit. Forconvenience, this is referred to as Type 2 CSI-RS as described above.

Referring to FIG. 16B, even in the Type 2 CSI-RS, the period/offsetparameter may be configured like the Type 1 CSI-RS (or a scheme in whicha period parameter is implicitly indicated/set through a point where theperiod/offset parameter is omitted and every time unit isrepresented/indicated is also available and for example, the CSI-RS maybe configured/limited in a type in which multiple time units areconsecutively (or contiguously) represented to be bursty, and this isassociated with an aperiodic CSI-RS configuration and a start time ofthe corresponding CSI-RS burst, etc. may be indicated) and in this case,an additional (time unit offset) parameter explicitly indicating aCSI-RS detailed transmission time depending on the (sub) time unit maybe together configured based on every CSI-RS transmission time indicatedby the corresponding period/offset parameter. In addition/alternatively,every CSI-RS transmission time may be defined/set/limited to the starttime of each time unit (as a default setting method) (for example, asillustrated in FIG. 16B) and a plurality of sub time units may beconfigured within one time unit. That is, one time unit may be dividedinto the plurality of sub time units. The sub time unit may be limitedto be continuously configured to be only consecutive (e.g., asillustrated in FIG. 16B). Alternatively, parameters associated with aseparate period/offset may be together configured with the separateperiod/offset so that each of the sub time units is more flexiblyconfigured within one time unit (eveninconsecutively/independently/separately).

FIG. 17 is a diagram illustrating a QCL assumption scheme depending on atype 2 CSI-RS configuration according to an embodiment of the presentinvention.

A configuration of a type 2 CSI-RS type may be used for a purpose forspecific (DL) beam management. For example, one type 2 CSI-RSconfiguration may be provided in a type to include/indicate/configureone or multiple CSI-RS resource(s) and when one type 2 CSI-RSconfiguration includes a configuration of multiple CSI-RS resources, itmay be characterfully limited that different CSI-RS resources are nottransmitted at the same time. That is, it may be limited that multipleCSI-RS resources are at least TDM and transmitted (based on eachresource unit) (as illustrated in FIG. 17).

Due to an advantage of such an operation, at least different/independent(analog) beams are applied among different CSI-RS resources and CSI-RSresources to which different (analog) beams are applied are transmittedto the UE at different times, and as a result, the UE may effectivelyperform a beam management procedure including an RX beam sweepingoperation therefor. Additionally, different/independent antenna portnumbers may be set for each CSI-RS resource. Alternatively, only thesame antenna port number may be limited to be set for each of alldifferent CSI-RS resources (according to a configuration of the eNB)under a specific condition.

In such a structure, another RS/signal(s) (group(s)) and/or specific SSblock index (or ID)(s) (including specific MRS-1, 2, and/or 3) whichassumes/establishes QCL or partial QCL with respect to specific QCLparameter(s)/characteristic(s) (e.g., at least one of Delay spread,Doppler spread, Doppler shift, Average gain, Average delay, Averageangle (AA), Angular spread (AS), and/or PAP) may be configured in the UE(in advance) ‘for each CSI-RS resource’. This may be configured in theUE through RRC signaling, MAC (L2) signaling, and/or DCI (L1) signaling.Accordingly, the UE may reduce implementation complexity and/or enhancedetection/measurement performance by positively applying/utilizingspecific QCL parameter(s)/characteristic(s) acquired through the QCL orpartial QCL when measuring the antenna ports within the CSI-RS resource.Hereinafter, for convenience of description, other RS/signal(s)(group(s)) (including specific MRS-1, 2, and/or 3) and/or specific SSblock index(s) which is QCL assumed or partial QCL assumed with theCSI-RS (target RS) may be collectively referred to as a ‘source RS (orQCL source/reference RS)’. Therefore, a QCL parameter (or LSP) of thetarget RS may be implicated/estimated from a QCL parameter (or LSP)estimated from the source RS.

In addition/alternatively, when there is a plurality of otherRS/signal(s) (group(s)) (including specific MRS-1, 2, and/or 3) and/orspecific SS block index(s) (i.e., ‘source RS’) which is QCL (or partialQCL) indicated for each CSI-RS resource, the UE may bedefined/configured to apply/perform a (partial) QCL assumption operationby union (or averaging or particular weighted averaging) of specific QCLparameter(s)/characteristic(s) for a plurality of source RSs indicatedfor each resource. In addition/alternatively, MRS-x (where x is anatural number such as x=1, 2, or 3) may also define/configure QCL orpartial QCL with the specific SS block index(s) with respect to thespecific QCL parameter(s)/characteristic(s) in advance.

Alternatively, in order to support more flexible eNB implementation,other RS/signal(s) (group(s)) ((including specific MRS-1, 2, and/or 3)and/or specific SS block index(s) which assumes/establishes QCL orpartial QCL with respect to specific QCL parameter(s)/characteristic(s)‘for each CSI-RS antenna port (or specific port group)’ within eachCSI-RS resource may be configured in the UE (in advance) in such astructure. This may be configured in the UE through RRC signaling, MAC(L2) signaling, and/or DCI (L1) signaling. Accordingly, the UE mayreduce implementation complexity and/or enhance detection/measurementperformance by positively applying/utilizing specific QCLparameter(s)/characteristic(s) acquired through the QCL or partial QCLwhen measuring the antenna ports within the CSI-RS resource.

In addition, when both the former CSI-RS resource-level QCLconfiguring/signaling scheme and the latter port-level QCLconfiguring/signaling scheme are supportable, the eNB may utilizeadditional flexibility regarding whether to provide QCLconfiguration/signaling for each CSI-RS resource as in the formerembodiment or whether to provide the QCL configuration/signaling foreach port-level as in the latter embodiment. That is, in the embodimentof FIG. 17, the QCL or partial QCL may be transformed/applied to a typeconfigured/indicated not by the resource unit but by each port unit inthe resource. In addition/alternatively, when there is a plurality ofother RS/signal(s) (group(s)) (including specific MRS-1, 2, and/or 3)and/or specific SS block index(s) (i.e., ‘source RS’) which is QCL (orpartial QCL) indicated for each CSI-RS port, the UE may bedefined/configured to apply/perform a (partial) QCL assumption operationby union (or averaging or particular weighted averaging) of specific QCLparameter(s)/characteristic(s) for a plurality of source RSs indicatedfor each resource. In addition/alternatively, MRS-x (where x is anatural number such as x=1, 2, or 3) may also define/configure QCL orpartial QCL with the specific SS block index(s) with respect to thespecific QCL parameter(s)/characteristic(s) in advance.

Meanwhile, for the purpose of the beam management, the UE may bedefined/configured to perform a report associated with the beammanagement purpose to the eNB. In this case, when the UE reports toabase station (e.g., gNB) index information of a p-th (e.g., p=1, 2, . .. P (settable by the eNB)) preferred (CSI-RS) port, informationregarding within CSI-RS resource the corresponding port is a port mayalso be continuously (or according to the configuration of the eNB)reported to the eNB in a type paired with the port index information.For example, when an indicator indicating which CSI-RS resource thecorresponding CSI-RS resource is referred to as a CSI-RS resourceindicator (CSI), reporting contents of the UE may be reported to the ENBin a type in which two indication information is paired like (CRI, portindex). In addition/alternatively, simultaneously, the UE may beconfigured to report a specific metric (e.g., RSRP, reference signalreceived quality (RSRQ), and/or CQI or a specific function similarthereto) which may represent/indicate a signal quality for the port.

As another modified embodiment of the reporting contents, the pairedinformation may be defined/configured to be configured in a type of{CRI, port selection codebook index (or PMI)} to be reported by the UE.In this case, in order to derive the port selection PMI, a “selectioncodebook: corresponding thereto may be pre-defined/configured. A size ofa vector corresponding to each index of the selection codebook coincideswith the number of CSI-RS ports in the CSI-RS resource indicated by thecorresponding/paired CRI and the vector corresponding to each index maybe configured in such a type (i.e., a selection codebook vector type) inwhich a value of only one specific element is 1 and all remainingelements are 0.

As described above, when one type 2 CSI-RS configuration isconfigured/provided in a type including one or K (K>1) CSI-RSresource(s), an upper limit value for a settable K value may exist.Information regarding a (maximum) K value that may besupported/implemented by the UE may be delivered to the eNB through UEspecific capability signaling during initial access and based thereon,the eNB may be limited to provide up to K CSI-Resources within one Type2 CSI-RS configuration. The eNB may configure K CSI-RS resourcessemi-statically in an RRC signaling form at the time of configuring onetype 2 CSI-RS based on such UE capability signaling information, etc.More specifically, a configuration/control operation may be supported inwhich only N (N<=K) CSI-RS resources are selectively activated throughL2 (e.g., by MAC CE) signaling (and/or L1 (e.g., by DCI) and L3signaling) among K CSI-RS resources which are RRC-configured (see FIG.17). In this case, the UE may recognize that the remaining (K-N) CSI-RSresources that are not activated are deactivated or terminated orseparate signaling for deactivation/termination may beprovided/supported to the UE. As a result, the UE may bedefined/configured to measure the signal quality for each portconfigured/included in each of N activated CSI-RS resources and comparemetrics acquired through the measured signal quality and report Ppreferred port information and/or a metric value (for each of Ppreferred ports) to the eNB.

A QCL definition in the NR may be determined by considering five largescale QCL parameters/characteristics such as delay spread, Dopplerspread, Doppler shift, average gain, and average delay. Furthermore, inaddition to the QCL parameters/characteristics, in order to support a UEside beam forming/receiving procedure, a QCL framework of the NR may beextended to new spatial QCL parameters (i.e., reception beam (Rx beam)related parameters) as described above. Such a spatial QCL parameter(i.e., reception beam related parameter) represents the QCLcharacteristic for a new arrival/reception angle, in particular whenanalog beamforming is applied to the UE side. During the beam managementprocedure, the UE may select several TX-RX analog beam pairs bymeasuring and comparing a quality of a specific DL RS (e.g., RRM-RS).The TRP may select one of the UE preferred Tx beams to transmit thebeamformed CSI-RS or DMRS ports. In this case, the UE should know whichRx beam should be configured to receive the antenna ports amongcandidate Rx beams so that a Tx beam ID corresponding to the RRM-RS portmay be signaled to the UE. In such a situation, it can be said that theRRM-RS port and the CSI-RS/DMRS port are QCL in terms of a dominantarrival/receiving angle.

The dominant arrival/receiving angle determines an Rx beamformingcoefficient and may be regarded as a relatively large-scalecharacteristic since an analog beam may not be dynamically changedrelative to a digital beam. Without the QCL assumption, the UE has tosearch for multiple RX beam candidates, which is energy and timeconsuming.

Therefore, when analog beamforming is applied in the UE, a new type ofQCL characteristic (e.g., ‘spatial QCL parameter (i.e., reception beamparameter)’) for the dominant arrival/receiving angle should be definedin the NR.

Considering the initial access-related discussion, the RRM-RS may bereferred to as MRS-1, 2, or 3 and may or may not be multiplexed withinthe SS block. Further, the RRM-RS may be a single or multi-beam RS. Inorder to support reasonable UE complexity in Rx beam search/sweeping,the CSI-RS related configuration through the RRC or MAC should at leastinclude the QCL (or partial QCL) indication for a specific MRS-x (x is anatural number, e.g. x=1, 2, or 3) or SS block index in terms of thespatial QCL parameter. In this case, the UE may assume that the PAP fromthe CSI-RS is a subset of the PAP observed from the MRS-x or SS block.It is considered that the TXRU used for the CSI-RS transmission needs tobe at least used for signal transmission in the SS block in an SFNmanner.

Thus, in order to support the reasonable UE complexity in the Rx beamsearch, the CSI-RS related configuration via the RRC or MAC shouldinclude a QCL indication (at least for the spatial QCL parameter) forthe SS block index. In this case, the UE may assume that the PAP fromthe CSI-RS is a subset of the PAP observed from the signals transmittedin the SS block.

To assist QCL association between reference signal resources/ports forUE spatial QCL parameter(s) to support the UE side beamforming/receivingprocedures, UE feedback and content need to be supported.

Detailed information for the beamforming/receiving procedure should beprovided, and it is desirable that performance should be assessed atleast from the viewpoint of the metrics below:

-   -   RS overhead    -   UE feedback overhead    -   Spectrum efficiency

The spatial parameters for the QCL in the NR describe spatial channelcharacteristics of the RS antenna ports observed at a receiver. Further,in the NR, the spatial parameter describes the spatial channelcharacteristics of the antenna port at a transmitter. If necessary, theUE may report information related thereto to the eNB.

The NR supports or does not support a downlink indication to derive theQCL assumption to support UE-side beamforming for downlink controlchannel reception.

A non zero power (NZP) CSI-RS resource in the NR may be at least definedas a set of NZP CSI-RS ports that are mapped to RE sets within afrequency span/duration that may be measured to derive the CSI. MultipleNZP CSI-RS resources may be at least configured in the UE to supportCoMP and a multiple beamforming CSI-RS based operation. Here, each NZPCSI-RS resource for CoMP may at least have a different number of CSI-RSports.

FIG. 18 is a diagram illustrating a (required) QCL indication for a type2 CSI-RS resource according to an embodiment of the present invention.

The QCL definition in the NR may be determined by considering five largeQCL parameters/characteristics such as delay spread, Doppler spread,Doppler shift, average gain, and average delay. Furthermore, in additionto the QCL parameters/characteristics, in order to support a UE sidebeam forming/receiving procedure, a QCL framework of the NR may beextended to new spatial QCL parameters (i.e., reception beam relatedparameters) as described above. Such a spatial QCL parameter (i.e.,reception beam related parameter) represents the QCL characteristic fora new arrival/reception angle, especially when analog beamforming isapplied to the UE side. During the beam management procedure, the UE mayselect several TX-RX analog beam pairs by measuring and comparing aquality of a specific DL RS (e.g., RS port(s) for RRM, may be referredto as ‘RRM-RS' for convenience). The TRP may select one of the UEpreferred Tx beams to transmit the beamformed CSI-RS or DMRS ports. Inthis case, the UE should know which Rx beam should be configured toreceive the antenna ports among candidate Rx beams so that a Tx beamdirection corresponding to the RRM-RS port may be signaled to the UEthrough a related QCL indication. In such a situation, it can be saidthat the RRM-RS port and the CSI-RS/DMRS port are QCL in terms of adominant arrival/receiving angle.

The dominant arrival/receiving angle determines the Rx beamformingcoefficient and may be regarded as the relatively large-scalecharacteristic since the analog beam may not be dynamically changedrelative to the digital beam. Without the QCL assumption, the UE has tosearch for multiple RX beam candidates, which is energy and timeconsuming.

Therefore, when analog beamforming is applied in the UE, a new type ofQCL characteristic (e.g., ‘spatial QCL parameter (i.e., reception beamparameter)’) for the dominant arrival/receiving angle should be definedin the NR.

Considering the initial access-related discussion, the RRM-RS may bereferred to as MRS-1, 2, or 3 and may or may not be multiplexed withinthe SS block. Further, the RRM-RS may be a single or multi-beam RS. Inorder to support reasonable UE complexity in Rx beam search/sweeping,the CSI-RS related configuration through the RRC or MAC should at leastinclude the QCL (or partial QCL) indication for a specific MRX-x (x is anatural number, e.g. x=1, 2, or 3) or SS block index in terms of thespatial QCL parameter. In this case, the UE may assume that the PAP fromthe CSI-RS is a subset of the PAP observed from the MRS-x or SS block.It is considered that the TXRU used for the CSI-RS transmission needs tobe at least used for signal transmission in the SS block in an SFNmanner.

Thus, in order to support the reasonable UE complexity in the Rx beamsearch, the CSI-RS related configuration via the RRC or MAC shouldinclude a QCL indication (at least for the spatial QCL parameter) forthe SS block index. In this case, the UE may assume that the PAP fromthe CSI-RS is a subset of the PAP observed from the signals transmittedin the SS block.

In regard to the CSI-RS configuration, the Type 1 CSI-RS resource (forMIMO CSI feedback) and the Type 2 CSI-RS resource (for supporting DLTx/Rx beam sweeping) (for DL beam management) are proposed as describedabove.

Referring to FIG. 18, each CSI-RS resource may have a QCLassumption/relationship with a specific SS block. Further, within oneCSI-RS resource, the CSI-RS ports may correspond to different analogbeams. In this case, the UE may report {CRI, Port Index} preferred bythe UE to the eNB for the DL beam management.

In order to measure the Type 1 CSI-RS resources for MIMO CSI feedback,the reasonable QCL signaling (e.g., QCL signaling for linking with theType 2 CSI-RS resource and port index pair) should be at least providedto the UE in order to assist the Rx beam configuration.

That is, on the configuration of the type 1 CSI-RS resource, informationindicating that the QCL or partial QCL assumption may be applied to atleast one of specific type 2 CSI-RS resource(s) and/or port index (or aspecific selection codebook index for the port index) within thecorresponding resource(s) and QCL parameter(s)/characteristic(s) may beprovided by L1 (e.g., by the DCI), L2 (e.g., by the MAC CE), and/or LE(e.g., by the RRC) signaling. The UE may reflect/apply the QCLassumption or partial QCL assumption in the Type 1 CSI-RS resourcemeasurement based on the signaling/configuration. In this case, wheninformation such as a specific MRS-x (e.g., x=1, 2, or 3, . . . ) and/ora specific SS block index indicated to be QCL or partial QCL for the QCLType 2 CSI-RS resource (and/or a specific port within that resource) ispresent, even the information is linked/considered to be applied tomeasurement of the type 1 CSI-RS resource, of course. That is, the UEmay consider/apply the QCL assumption/relationship between the type 2CSI-RS resource/port and the MRS-x or SS block as well as the QCLassumption/relationship between the Type 1 CSI-RS resource and the Type2 CSI-RS resource/port.

In this case, by a specific condition and a specific configuration, theQCL or partial QCL indication for the specific type 2 CSI-RS resource(s)and/or the port index in the corresponding resource is applied only fora purpose of a linkage indication (not for a purpose of actual QCLassumption) to limit the operation of the UE so as to apply only the QCLor partial QCL assumption for the specific MRS-x (e.g., x=1, 2, or 3, .. . ) and/or the specific SS block index QCL connected with the specifictype 2 CSI-RS resource(s) and/or the port index within the correspondingresource. Therefore, in this case, the UE may not perform the QCLassumption with the type 2 CSI-RS resource/port QCL indicated with thetype 1 CSI-RS resource but perform the QCL assumption with the MRS-xand/or SS block QCL indicated with the type 2 CSI-RS resource/port atthe time of measuring the type 1 CSI-RS resource.

In addition/alternatively, on the configuration of the type 1 CSI-RSresource, information indicating that the QCL or partial QCL assumptionmay be applied to at least one of QCL parameter(s)/characteristic(s)directly with specific MRS-x (e.g., x=1, 2, or 3, . . . ) and/or aspecific SS block index may be provided by L1 (e.g., by the DCI), L2(e.g., by the MAC CE), and/or LE (e.g., by the RRC) signaling. The UEmay reflect/apply the QCL assumption or partial QCL assumption in theType 1 CSI-RS resource measurement based on the signaling/configuration.

That is, the QCL assumption/relationship with the SSB block may beconfigured/indicated in the CSI-RS ‘resource’ unit/level as in theembodiment of FIG. 17, and as an additional/modified embodimenttherefor, the QCL assumption/relationship with the SSB block may also beconfigured/indicated even at the CSI-RS ‘port’ unit/level (i.e., moreprecisely) within each CSI-RS resource. Thus, in the embodimentsproposed in this specification, although not otherwise mentioned,embodiments described in terms of CSI-RS port unit/level may be derivedas embodiments replaced with CSI-RS resource unit/level, of course andvice versa.

FIG. 19 is a diagram illustrating an overall DL beam managementprocedure according to an embodiment of the present invention. Inparticular, FIG. 19 illustrates a QCL relationship between the CSI-RSresource and the SS block (or MRS-1).

Referring to FIG. 19, a beam-width of an SFN-transmitted SS block (whichis QCL with the Type 2 CSI-RS resource) may be divided/segmented aplurality of transmitted CSI-RS ports within one CSI-RS resource andrespective CSI-RS ports may correspond to different analog beams by gNBimplementation.

Conclusions derived from the aforementioned contents may be summarizedas follows:

Conclusion 1: When the analog beamforming is applied on the UE side, anew type of QCL characteristic for dominant arrival/receiving angleshould be defined in the NR.

Conclusion 2: In order to support the reasonable UE complexity in the Rxbeam search, the CSI-RS related configuration via the RRC or MAC shouldinclude at least a QCL indication with the SS block index for thespatial QCL parameter(s). Here, the UE may assume that the PAP from theCSI-RS is a subset of the PAP observed from the signals transmitted inthe SS block.

Conclusion 3: In order to support the reasonable UE complexity in the Rxbeam search, the Type 2 CSI-RS resource needs to be at least configuredto form a reasonable QCL linkage with MRS-1 or SS block with respect tothe spatial QCL parameter.

The QCL relationship as shown in Table 5 below may beproposed/summarized as an embodiment or an additional proposaldescription item according to at least one of the proposed schemesdiscussed above. At least one of sets x-y included in Table 5 may bedefined/configured on the wireless communication system andconfiguration/signaling may be provided via RRC, MAC, and/or DCI foreach RS/RS resource to be configured.

TABLE 5 Type of QCL Example pairs of RSs/RS parameter set QCL parametersresource Application case Set 1-1 {Doppler Shift, average BetweenPSS/SSS and Initial acquisition delay, spatial QCL} PBCH DMRS, within anSS block Set 1-2 {Doppler Shift, average Across SS blocks within aInitial acquisition (FFS on spec delay} cell descriptions) Set 2-1{Doppler Shift, average Between an SS CSI-RS delay} block(PBCH DMRS) andmeasurement and CSI-RS F/T tracking Set 2-2 {(Partial) spatial QCL,Between an SS CSI-RS Doppler Shift, average block(PBCH DMRS) andmeasurement (for delay} CSI-RS, the agreed “beam Between CSI-RS and CSI-indication” case)* RS and F/T tracking Set 3-1 {Spatial QCL, averageBetween an SS block and Demodulation for delay, delay spread, DMRScommon PDCCH Doppler Spread, and broadcast Doppler Shift} PDSCH Set 3-2{Spatial QCL, average Between CSI-RS(s) and Demodulation delay, delayspread, DMRS (It is possible by Doppler Spread, agreement** that DopplerShift} multiple CSI-RSs, each QCLed per DMRS port group, can besignaled)

As shown in Table 5, a plurality of QCL parameter set types may bedefined, which is a form in which a ‘source RS/signal/resource (alsoreferred to as a QCL source)’ and a ‘QCL parameter/type’ QCL assumedwith a target RS/signal/resource (e.g., CSI-RS) are jointly encoded. TheeNB may indicate QCL application by selectively signaling (e.g., RRC,MAC, and/or DCI signaling) to the UE a specific type of a plurality ofpredefined QCL parameter set types according to an application case.

Further, Table 5 may also be interpreted as being defined as a pluralityof QCL parameter set types for each grouped QCL parameter group orsource RS/signal/resource (i.e., a form in which two information is notjointly encoded but the plurality of QCL parameter set types is definedonly for any one information). In other words, each QCL parameter settype may be interpreted as being defined to indicate ‘only specific QCLparameter group information’ or ‘only source RS/signal/resourceinformation’. In this case, the eNB may indicate QCL application bysignaling (e.g., RRC, MAC, and/or DCI signaling) to the UE otherinformation excluded from joint encoding together or separately whileindicating the specific QCL parameter set type. For example, the eNB mayindicate to the UE QCL parameter set type 2-2 ({(Partial) spatial QCL,Doppler Shift, average delay}) and a source RS/signal/resource to be QCLapplied, which corresponds thereto (e.g., signaling as a form of {DL RSID/index, QCL parameter set type}).

As described above, in the NR, the QCL indication between antenna portsof two CSI-RS resources may be supported. Basically no QCL should beassumed between the antenna ports of two CSI-RS resources and in thiscase, a partial QCL parameter (e.g. only the spatial QCL parameter ofthe UE side) may be considered.

In the case of the DL, the NR may support CSI-RS reception with orwithout a beam related indication. When the beam related indication isprovided, information regarding the UE side beamforming/receivingprocedure used for CSI-RS based measurement may be indicated to the UEthrough the QCL. In this case, QCL information includes a spatialparameter for receiving the UE side CSI-RS port.

In the case of 3- and 4-layer transmission, the NR supports one codeword(CW) per UE and per PDSCH/PUSCH allocation.

DMRS port groups belonging to one CW may have different QCL assumptions.One UL- or DL-related DCI may include one MCS per CW. One CQI per CW maybe calculated.

At least for a purpose of beam indication for NR unicast PDSCH, the NRmay support N (N may be configured up to “3”)-bit indicator bit withinthe DCI providing a reference to the DL RS spatially QCLed with at leastone PDSCH DMRS port group.

An indicator state may be associated with an index (e.g., a CRI, SSBindex) of at least one DL RS and each index of the DL RS may beassociated with a given DL RS type (e.g., aperiodic CSI-RS, periodicCSI-RS, semi-persistent CSI-RS, or SSB). One possibility of DL CSI-RStype determination is using a resource setting ID, but is not limitedthereto.

The NR may support a QCL indication of DM-RS for PDSCH through DCIsignaling. The N-bit indicator field described above may be extended tosupport the following functions:

-   -   Each state may indicate one or two RS sets indicating/having the        QCL relationship for each of one or two DMRS port groups.    -   Each RS set represents one or more RS(s) QCLed with DM-RS ports        in the corresponding DM-RS group. The RSs in the RS set may be        of different types.

When there one or more RSs per RS set, each of the RSs may be associatedwith a different QCL parameter. For example, one RS may be associatedwith a spatial QCL, while another RS may be associated with another QCLparameter. The RS setting for each state may be performed via higherlayer signaling (e.g., RRC/RRC+MAC CE).

A method for configuring the QCL relationship between the reference RSand the target RS may be supported in the NR as follows:

-   -   When the QCL relationship is configured, at least the spatial        QCL relationship may be signaled between the SS block        (source/reference RS) and at least periodic (P)/semi-persistent        (SP) CSI-RS (target RS).    -   When the QCL relationship is configured, at least the spatial        QCL relationship may be signaled between a P/SP CSI-RS resource        (source/reference RS) and at least another P/SP CSI-RS (target        RS).

Further, in the NR, the following functions may be at least supportedfor at least single component carrier (CC)/bandwidth part (BWP) andsingle TRP:

Antenna port(s) of the NZP CSI-RS may be QCLed with the antenna port(s)of the other RS for the following parameters:

-   -   QCL with at least one of the tracking reference signal (TRS) for        (average delay, delay spread, Doppler shift, and/or Doppler        spread), the SS block for (spatial Rx parameter(s)), or the NZP        CSI-RS for (spatial Rx parameter(s)).

The antenna port of the DM-RS may be QCLed with the SS block withrespect to (average delay, delay spread, Doppler shift, Doppler spread,and/or spatial Rx parameter) for PDSCH demodulation before TRSconfiguration.

Antenna port(s) of the NZP CSI-RS may be QCLed with the antenna port(s)of another RS for the following parameters:

-   -   QCL with the SS block with respect to (average delay, delay        spread, Doppler shift, Doppler spread, and/or spatial Rx        parameter)

The antenna port of the DM-RS may be QCLed with the NZP CSI-RS withrespect to (average delay, delay spread, Doppler shift, Doppler spread,and/or spatial Rx parameter). Further, the antenna port of the DM-RS maybe QCLed with the TRS with respect to (average delay, delay spread,Doppler shift, Doppler spread, and/or spatial Rx parameter).

Various RS combinations with the QCL assumption may be proposed asfollows, according to before or after TRS and CSI-RS RRC establishment:

1. Above and below 6 GHz, before RRC setting of TRS and CSI-RS:

-   -   SSB→DMRS (the SSB is the source RS and the DMRS for PDSCH is the        target RS) for PDSCH, i.e., the DMRS for PDSCH is QCLed with the        SSB with respect to (Doppler shift, Doppler spread, average        delay, delay spread, and/or spatial Rx parameter (the spatial RX        parameter is used only at 6 GHz or higher)).    -   SSB→DMRS (the SSB is the source RS and the DMRS for PDSCH is the        target RS) for PDCCH, i.e., the DMRS for PDCCH is QCLed with the        SSB with respect to (Doppler shift, Doppler spread, average        delay, delay spread, and/or spatial Rx parameter (the spatial RX        parameter is used only at 6 GHz or higher)).

2. Below 6 GHz for single TRP, after RRC setting of TRS and CSI-RS:

-   -   SSB (also available in another component carrier (CC)+TRS+CSI-RS        for CSI acquisition+DMRS for PDSCH    -   SSB→TRS (the SSB is the source RS and the TRS is the target RS):        (Doppler shift and/or average delay), i.e., TRS is QCLed for the        SSB with respect to (Doppler shift and/or average delay).

Further, type A and type B may be defined as follows according to theQCL scheme.

1. Type A:

-   -   TRS (source RS)→CSI-RS (target RS) for CSI acquisition: Doppler        shift, Doppler spread, average delay, and/or delay spread    -   TRS/CSI-RS (source RS)→DMRS (target RS): Doppler shift, Doppler        spread, average delay, and/or delay spread

That is, the type A may be defined to indicate ‘the CSI-RS for CSIacquisition may be QCLed with the TRS with respect to Doppler shift,Doppler spread, average delay, and/or delay spread and the DMRS may beQCLed with the DMRS with respect to Doppler shift, Doppler spread,average delay, and/or delay spread’.

2. Type B:

-   -   TRS (source RS)→CSI-RS (target RS) for CSI acquisition: Doppler        shift and/or Doppler spread    -   CSI-RS (for the CSI acquisition)→DMRS: Doppler shift, Doppler        spread, average delay, and/or delay spread

That is, the type B may be defined to indicate ‘the CSI-RS for CSIacquisition may be QCLed with the TRS with respect to Doppler shiftand/or Doppler spread and the DMRS may be QCLed with the CSI-RS withrespect to Doppler shift, Doppler spread, average delay, and/or delayspread’. The type B may be applied for a CoMP operation of the eNB.

A wide beam TRS may be QCLed with a narrow beam CSI-RS and the wide beamCSI-RS may be QCLed with a narrow beam DMRS.

The RS combination, which is assumed to be QCL for a case after RRCsetting at 6 GHz or more, will be described below.

Meanwhile, the N-bit indicator (in particular, a signaling mechanism forlinkage between the DL RS index (e.g., CRI, SSB index) and the indicatorstate) of the DCI described above should be based on an explicitsignaling scheme similar to an LTE PQI field in which a PQI state isexplicitly described by RRC signaling. Further, in order to maintain thesame spatial QCL assumption between PDCCH DMRS and PDSCH DMRS, the N-bitindicator of the DCI may have a default state description on the samespatial QCL assumption.

In other words, an explicit signaling mechanism for linking the DL RSindex (e.g., CRI, SSB index) with indicator state should be at leastsupported, and the support of the linkage may be implicitly determinedby the UE.

The indicator state may include or may not include other parameters(e.g., another QCL parameter for a mapping purpose to the RE from PDSCHsimilar to PQI in LTE). Such a joint encoding scheme may be supportedsimilar to LTE to maintain better trade-offs in DCI overhead andflexibility and may be achieved by appropriately expanding a value of Nabove [3 bits]. That is, together with the PDSCH beam indication, PDSCHrate matching information which may include a PDSCH start symbol (toprovide a beam switching time interval, a DCI decoding time, and a ZPCSI-RS resource for protecting the CSI-RS of a neighboring beam) needsto be indicated. Therefore, joint encoding between the PDSCH beamindication and the PDSCH rate matching information may be supported inorder to reduce the DCI overhead.

With respect to an issue that the RS set for each state may beconfigured via the higher layer signaling such as RRC or RRC+MAC CE,this specification proposes that the NR supports RRC+MAC CE signaling inthe NR to update that each indicator state is updated by MAC CE. Thismay enhance efficiency and flexibility in terms of networkimplementation. That is, in this case, the configuration of the RS setfor each state may be performed even through RRC+MAC CE as well as RRC.

In the case of a QCL application timing related with a QCL indicationtime, in order to change/apply the PDSCH beam according to the PDCCHindication, at least one slot latency or two symbols for a timing gapfor accurately decoding the PDCCH should be permitted. That is, at leastone slot latency or two symbols (latency) should be permitted for theQCL application timing related with the QCL indication time.

With respect to the indicator state, the mentioned spatial QCL relationbetween a reference RS and a targeted RS is an independent feature ofthe spatial QCL indication for PDSCH reception. Therefore, twoindicators themselves may be actually separated into independent DCIfields/formats. That is, the indicator for the spatial QCL relationshipbetween the reference RS and the target RS may be supported as a DCIfield/format separated/independent from the spatial QCL indicator forPDSCH reception.

The spatial QCL relationship between the reference RS and the target RSmay be proposed as follows.

Signaling for the spatial QCL relationship between the SS block(reference RS) and at least P/SP CSI-RS may be performed even throughRRC+MAC CE as well as RRC, and as a result, higher efficiency andflexibility may be generated in terms of beam control. Further, theaperiodic (AP) CSI-RS may be supported to be permitted with respect tothe target RS and this means that the beam indication is preconfiguredby RRC+MAC CE, but an actual transmission timing of the AP CSI-RS may beindicated similar to an AP CSI-RS concept of LTE, which is introduced byeFD-MIMO.

Signaling for the spatial QCL relationship between the P/SP CSI-RSresource (reference RS) and another/different P/SP CSI-RS resource mayalso be performed even through RRC+MAC CE as well as RRC and thisprovides higher efficiency and flexibility to the beam control. Further,due to such a reason, the AP CSI-RS may be supported to be permittedwith respect to the target RS.

In conclusion, the signaling for the spatial QCL relationship betweenthe SS block (reference RS) and at least P/SP CSI-RS may be performedeven through RRC+MAC CE as well as RRC and the AP CSI-RS may also bepermitted as the target RS. Further, signaling for the spatial QCLrelationship between the P/SP CSI-RS resource (reference RS) andanother/different P/SP CSI-RS resource may also be performed eventhrough RRC+MAC CE as well as RRC and the AP CSI-RS may also bepermitted as the target RS.

The QCL parameter set and a related condition for the NZP CSI-RS QCL andthe DMRS QCL may be proposed as follows.

Antenna port(s) of the NZP CSI-RS may be QCLed with the antenna port(s)of the following other RS for the following parameters:

-   -   TRS for {average delay, delay spread, Doppler shift, and/or        Doppler spread}, the SS block for {spatial Rx parameter}, or the        NZP CSI-RS for {spatial Rx parameter}.    -   SS block for {average delay, delay spread, Doppler shift,        Doppler spread, and, spatial Rx parameter} (regardless of        whether the TRS is configured)

Further, for the DMRS QCL, the following matters should be additionallysupported:

-   -   The antenna port of the DM-RS may be QCLed with the NZP CSI-RS        with respect to {average delay, delay spread, Doppler shift,        Doppler spread, and spatial Rx parameter}.    -   The antenna port of the DM-RS may be QCLed with the SS block        with respect to {average delay, delay spread, Doppler shift,        Doppler spread, and spatial Rx parameter} for PDSCH demodulation        (before NZP CSI-RS configuration).

According to the proposal for the DMRS QCL, since all available requiredoperations are sufficiently covered in the NR, the followingfunction/operation may no longer need to be supported.

-   -   The antenna port of the DM-RS may be QCLed with the TRS with        respect to {average delay, delay spread, Doppler shift, Doppler        spread, and/or spatial Rx parameter}.

Antenna port(s) of the NZP CSI-RS may be QCLed with the antenna port ofthe following other RS for the following QCL parameter:

-   -   SS block: The antenna port of the DM-RS may be QCLed with the        NZP CSI-RS with respect to {average delay, delay spread, Doppler        shift, Doppler spread, and/or spatial Rx parameter} (regardless        of whether the TRS is configured). Further, the antenna port of        the DM-RS may be QCLed with the SS block with respect to        (average delay, delay spread, Doppler shift, Doppler spread,        and/or spatial Rx parameter) for PDSCH demodulation before NZP        CSI-RS configuration.

Meanwhile, in the case of Type B above 6 GHz described above, it issufficient to add/define the spatial parameter to Type B defined in thecase of below 6 GHz described above. Type B may be supported as in theLTE, and Type B in the case of above 6 GHz may be defined specificallyas follows (or to indicate the following QCL operation):

-   -   TRS (source RS)→CSI-RS (target RS) for CSI acquisition: {Doppler        shift and/or Doppler spread}    -   CSI-RS (source/reference RS)→DMRS: {Doppler shift, Doppler        spread, average delay, delay spread, and/or spatial Rx        parameter}

That is, the type B in the case of above 6 GHz may be defined toindicate ‘the CSI-RS for CSI acquisition may be QCLed with the TRS withrespect to Doppler shift and/or Doppler spread and the DMRS may be QCLedwith the CSI-RS with respect to Doppler shift, Doppler spread, averagedelay, delay spread, and/or spatial Rx parameter’.

This means that the ‘spatial Rx parameter (of the DMRS) should be QCLassumed/directed only through the CSI-RS and not the TRS, so that thespatial Rx parameter should match the proposed technique for DL beammanagement based on the CSI-RS. This may be further utilized toefficiently support a dynamic point/beam selection operation in the NR.

In conclusion, Type B QCL may also be supported as in the LTE, and TypeB descriptions in the case of above 6 GHz should include the spatial Rxparameter to be indicated the CSI-RS rather than the TRS based on the DLbeam management operation supported by the NR.

At this time, for the sake of network flexibility, it is possible toconfigure/indicate which operation/type to follow through the RRC, MACCE, and/or DCI while defining an applicable range of the spatial Rxparameters as follows:

First embodiment) Type B in the case of above 6 GHz:

-   -   TRS (source RS)→CSI-RS (target RS) for CSI acquisition: Doppler        shift, Doppler spread, average delay, and/or spatial Rx        parameter    -   CSI-RS (source/reference RS)→DMRS (target RS): Doppler shift,        Doppler spread, average delay, and/or delay spread

and/or

Second embodiment) Type B in the case of above 6 GHz:

-   -   TRS (source RS)→CSI-RS (target RS) for CSI acquisition: Doppler        shift, Doppler spread, average delay, and/or spatial Rx        parameter    -   CSI-RS (source/reference RS)→DMRS (target RS): Doppler shift,        Doppler spread, average delay, delay spread, and/or spatial Rx        parameter

FIG. 20 is a flowchart illustrating a CSI-RS receiving method by a UEaccording to an embodiment of the present invention. The description ofthe above-described embodiments may be applied in the same or similarmanner with respect to this flowchart, and duplicated description willbe omitted.

First, the UE may receive an SSB (S2010). Here, the SSB may refer to aspecific block including PSS, SSS, and/or PBCH. In this case, the PSS,the SSS, and/or the PBCH may be transmitted within the SSB.

Next, the UE may receive a CSI-RS associated with the SSB. In this case,the CSI-RS may correspond to a periodic CSI-RS or an aperiodic CSI-RS.Further, in this case, the CSI-RS may be a CSI-RS transmitted for apurpose of beam management, not for a purpose of CSI acquisition.

In this case, the UE may receive the CSI-RS by performing QCL assumptionbetween the CSI-RS and the SSB. That is, the CSI-RS is QCL assumed withthe SSB to be received by the UE. This may be expressed that the CSI-RSand the SSB have a QCL relationship. Alternatively, it may be expressedthat the QCL relationship/assumption is established between the antennaport(s) transmitting the CSI-RS and the antenna port(s) transmitting theSSB. Alternatively, it may be expressed that the QCLrelationship/assumption is established between at least one CSI-RSresource/configuration and the SSB to which the CSI-RS is mapped (orwhich are used for transmitting the CSI-RS).

When the CSI-RS is mapped to a plurality of CSI-RS resources,application (or activation) of the QCL assumption may be selectivelyindicated in units of each CSI-RS resource. The application (oractivation) indication may be received by the UE through RRC signaling.

Further, when the QCL assumption with the SSB corresponds to partial QCLassumption, a QCL parameter of the CSI-RS may be assumed to correspondto a subset of the QCL parameters derived from the SSB.

Meanwhile, although not shown in the flowchart, a CSI-RS receivingmethod of the UE may further include receiving QCL information forindicating the QCL assumption between the CSI-RS and the SSB. In thiscase, the QCL information may indicate an index (or ID) of the SSB to beQCLed with the CSI-RS and a QCL type for a QCL parameter set to whichthe QCL assumption is applied. That is, the QCL information may includeindex (or ID) information of the SSB and QCL type information regardingthe QCL parameter set to which the QCL assumption is to be applied. TheQCL information may be received by the UE through the RRC signaling. TheQCL type may be predefined to indicate different sets of QCL parametersfor each QCL type and the QCL parameter set may include delay spread,Doppler spread, Doppler shift, average gain, average delay, and/or aspatial reception parameter. For example, QCL type A may be predefinedto indicate a QCL parameter set including Doppler shift, average delay,and spatial QCL parameters and QCL type B may be predefined to indicatea QCL parameter set including Doppler shift and average delayparameters. Here, the spatial reception parameter may include areception beam direction parameter and/or a reception beam width relatedparameter.

However, the QCL type indicated for the QCL assumption between theCSI-RS and the SSB may be pre-limited to a specific QCL type. Forexample, the specific QCL type may be limited/restricted to a QCL typeindicating a QCL parameter set including average delay, Doppler shift,and/or spatial reception parameters. Thus, when indicating/configuringthe QCL assumption between the CSI-RS and the SSB, the eNB mayconfigure/indicate the QCL assumption in the UE only in the QCL typeindicating the QCL parameter set including average delay, Doppler shift,and/or spatial reception parameters (or configured to have at least oneof average delay, Doppler shift, and/or spatial reception parameters).

General device to which present invention may be applied

FIG. 21 is a block diagram of a wireless communication device accordingto an embodiment of the present invention.

Referring to FIG. 21, a wireless communication system includes a basestation (BS) (or eNB) 2110 and a plurality of terminals (or UEs) 2120located within coverage of the BS 2110.

The eNB 2110 includes a processor 2111, a memory 2112, and a radiofrequency (RF) unit 2113. The processor 2111 implements functions,processes and/or methods proposed in above-describes. Layers of radiointerface protocols may be implemented by the processor 2111. The memory2112 may be connected to the processor 2111 to store various types ofinformation for driving the processor 2111. The RF unit 2113 may beconnected to the processor 2111 to transmit and/or receive a wirelesssignal.

The UE 2120 includes a processor 2121, a memory 2122, and a radiofrequency (RF) unit 2123. The processor 2121 implements functions,processes and/or methods proposed in above-described embodiments. Layersof radio interface protocols may be implemented by the processor 2121.The memory 2122 may be connected to the processor 2121 to store varioustypes of information for driving the processor 2121. The RF unit 2123may be connected to the processor 2121 to transmit and/or receive awireless signal.

The memory 2112 or 2122 may be present within or outside of theprocessor 2111 or 2121 and may be connected to the processor 2111 or2121 through various well known units. Also, the eNB 2110 and/or the UE2120 may have a single antenna or multiple antennas.

The aforementioned embodiments are achieved by combination of structuralelements and features of the present invention in a predeterminedmanner. Each of the structural elements or features should be consideredselectively unless specified separately. Each of the structural elementsor features may be carried out without being combined with otherstructural elements or features. Also, some structural elements and/orfeatures may be combined with one another to constitute the embodimentsof the present invention. The order of operations described in theembodiments of the present invention may be changed. Some structuralelements or features of one embodiment may be included in anotherembodiment, or may be replaced with corresponding structural elements orfeatures of another embodiment. Moreover, it will be apparent that someclaims referring to specific claims may be combined with another claimsreferring to the other claims other than the specific claims toconstitute the embodiment or add new claims by means of amendment afterthe application is filed.

Meanwhile, the expression of ‘A and/or B’ used in this specification maybe construed as meaning at least one of A and B.

An embodiment of the present invention may be implemented by variousmeans, for example, hardware, firmware, software or a combination ofthem. In the case of implementations by hardware, an embodiment of thepresent invention may be implemented using one or moreApplication-Specific Integrated Circuits (ASICs), Digital SignalProcessors (DSPs), Digital Signal Processing Devices (DSPDs),Programmable Logic Devices (PLDs), Field Programmable Gate Arrays(FPGAs), processors, controllers, microcontrollers and/ormicroprocessors.

In the case of implementations by firmware or software, an embodiment ofthe present invention may be implemented in the form of a module,procedure, or function for performing the aforementioned functions oroperations. Software code may be stored in the memory and driven by theprocessor. The memory may be placed inside or outside the processor, andmay exchange data with the processor through a variety of known means.

It is evident to those skilled in the art that the present invention maybe materialized in other specific forms without departing from theessential characteristics of the present invention. Accordingly, thedetailed description should not be construed as being limitative fromall aspects, but should be construed as being illustrative. The scope ofthe present invention should be determined by reasonable analysis of theattached claims, and all changes within the equivalent range of thepresent invention are included in the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention applied to a 3GPP LTE/LTE-A/NR system is primarilydescribed as an example, but may be applied to various wirelesscommunication systems in addition to the 3GPP LTE/LTE-A/NR system.

1. A method for receiving a channel state information (CSI)-referencesignal (RS) by a user equipment (UE) in a wireless communication system,the method comprising: receiving synchronization signal blocks (SSBs)based on a plurality of SSB indexes; receiving CSI-RS configurationinformation; receiving a CSI-RS based on the CSI-RS configurationinformation and the SSBs, wherein the CSI-RS configuration informationincludes i) information for a plurality of CSI-RS resources and ii) QCLinformation for each of the plurality of CSI-RS resources, wherein aspatial property of a beam related to transmission of the CSI-RS isindependent for each of the plurality of CSI-RS resources, and whereinbased on i) the CSI-RS is related to a specific CSI-RS resource amongthe plurality of CSI-RS resources and ii) the QCL information related tothe specific CSI-RS resource represents a specific SSB index among theplurality of SSB indexes: the CSI-RS is assumed to be quasi co-located(QCL) with an SSB based on the specific SSB index, with respect to aspatial reception parameter.
 2. The method of claim 1, wherein the SSBincludes at least one of a primary synchronization signal (PSS), asecondary synchronization signal (SSS), or a physical broadcast channel(PBCH).
 3. The method of claim 1, wherein the CSI-RS configurationinformation is received through radio resource control (RRC) signaling.4. The method of claim 1, wherein the QCL information includes a QCLtype for a QCL parameter set to which the QCL assumption is applied. 5.The method of claim 4, wherein the QCL type is defined to indicatedifferent QCL parameter sets for each QCL type.
 6. The method of claim5, wherein the QCL parameter set includes at least one of a delayspread, a Doppler spread, a Doppler shift, an average delay or thespatial reception parameter.
 7. The method of claim 1, wherein thespatial reception parameter includes at least one of a reception beamdirection parameter or a reception beam width related parameter.
 8. Themethod of claim 4, wherein the QCL type related to the QCL assumption isbased on a specific QCL type.
 9. The method of claim 8, wherein a QCLparameter set related to the specific QCL type includes the spatialreception parameter.
 10. The method of claim 1, wherein the CSI-RS isbased on a periodic CSI-RS.
 11. A method for transmitting a channelstate information (CSI)-reference signal (RS) by a base station in awireless communication system, the method comprising: transmittingsynchronization signal blocks (SSBs) based on a plurality of SSBindexes; transmitting CSI-RS configuration information; transmitting aCSI-RS based on the CSI-RS configuration information and the SSBs,wherein the CSI-RS configuration information includes i) information fora plurality of CSI-RS resources and ii) QCL information for each of theplurality of CSI-RS resources, wherein a spatial property of a beamrelated to transmission of the CSI-RS is independent for each of theplurality of CSI-RS resources, and wherein based on i) the CSI-RS isrelated to a specific CSI-RS resource among the plurality of CSI-RSresources and ii) the QCL information related to the specific CSI-RSresource represents a specific SSB index among the plurality of SSBindexes: the CSI-RS is assumed to be quasi co-located (QCL) with an SSBbased on the specific SSB index, with respect to a spatial receptionparameter.
 12. The method of claim 11, wherein the SSB includes at leastone of a primary synchronization signal (PSS), a secondarysynchronization signal (SSS), or a physical broadcast channel (PBCH).13. The method of claim 11, wherein the CSI-RS configuration informationis transmitted through radio resource control (RRC) signaling.
 14. Themethod of claim 11, wherein the QCL information includes a QCL type fora QCL parameter set to which the QCL assumption is applied.
 15. Themethod of claim 14, wherein the QCL type is defined to indicatedifferent QCL parameter sets for each QCL type.
 16. The method of claim15, wherein the QCL parameter set includes at least one of a delayspread, a Doppler spread, a Doppler shift, an average delay or thespatial reception parameter.
 17. The method of claim 11, wherein thespatial reception parameter includes at least one of a reception beamdirection parameter or a reception beam width related parameter.
 18. Themethod of claim 14, wherein the QCL type related to the QCL assumptionis based on a specific QCL type.
 19. The method of claim 11, wherein theCSI-RS is based on a periodic CSI-RS.
 20. A base station fortransmitting a channel state information (CSI)-reference signal (RS) ina wireless communication system, the base station comprising: a radiofrequency (RF) unit transmitting and receiving a radio signal; and aprocessor controlling the RF unit, wherein the processor is configuredto: transmit synchronization signal blocks (SSBs) based on a pluralityof SSB indexes, transmit CSI-RS configuration information, transmit aCSI-RS based on the CSI-RS configuration information and the SSBs,wherein the CSI-RS configuration information includes i) information fora plurality of CSI-RS resources and ii) QCL information for each of theplurality of CSI-RS resources, wherein a spatial property of a beamrelated to transmission of the CSI-RS is independent for each of theplurality of CSI-RS resources, and wherein based on i) the CSI-RS isrelated to a specific CSI-RS resource among the plurality of CSI-RSresources and ii) the QCL information related to the specific CSI-RSresource represents a specific SSB index among the plurality of SSBindexes: the CSI-RS is assumed to be quasi co-located (QCL) with an SSBbased on the specific SSB index, with respect to a spatial receptionparameter.